This review discusses recent progress in large-scale programmable silicon photonic chips for signal processing in various applications, including microwave photonics, optical communications, optical computing, quantum photonics, and dispersion control. The paper emphasizes the challenges and solutions for realizing and controlling these chips, focusing on waveguide loss, fabrication tolerance, power consumption, and control methods. It highlights the development of high-performance building blocks, such as ultra-low-loss silicon photonic waveguides, 2×2 Mach-Zehnder switches (MZSs), and microring resonator (MRR) switches. The paper also discusses methods for configuring large-scale programmable silicon photonic chips and summarizes representative examples for applications like beam steering, optical switching, optical computing, quantum photonic processing, and optical dispersion control. Finally, it provides an outlook on the challenges of further developing large-scale programmable silicon photonic chips. The paper reviews the progress in silicon photonic waveguides, which are crucial for low-loss signal processing. It discusses various methods to reduce waveguide loss, including improved fabrication processes and optimized mode field distributions. The paper also covers silicon photonic switches, including MZSs and MRRs, which are essential for optical signal processing. It discusses the performance requirements of optical switches, such as low losses, high extinction ratios, low power consumption, and low polarization sensitivity. The paper highlights the development of low-phase-error MZSs and MRRs, which are important for reducing random phase errors and improving the performance of optical switches. The paper also discusses programming strategies for large-scale optical signal processors, including self-configuring methods and the use of low-phase-error tuning elements. It highlights the importance of efficient programming strategies for achieving high-performance optical signal processors. The paper reviews the development of large-scale delay line arrays for signal processing, including MRR-based delay lines and long-waveguide-based delay lines. It discusses the applications of these delay lines in microwave photonic beamforming and optical signal processing. The paper also discusses large-scale optical switch arrays, including TO switches, EO switches, and MEMS switches. It highlights the advantages of these switches, such as low crosstalk, high extinction ratios, and low power consumption. The paper discusses the development of large-scale feedforward/backward optical signal processors, which offer more functional flexibility and convenient incorporation of tuning elements for microwave signal processing. It highlights the use of mesh-based computing processors, which allow the independent amplitude and phase control of photonic signals and can be configured to perform arbitrary unitary transformations on input vectors of coherent light modes. The paper concludes with an outlook on the challenges of further developing large-scale programmable silicon photonic chips, emphasizing the need for further improvements in waveguide loss, fabrication tolerance, power consumption, and control methods. It highlights the importance of these improvements for achieving high-performance optical signal processors and their applications in various fields.This review discusses recent progress in large-scale programmable silicon photonic chips for signal processing in various applications, including microwave photonics, optical communications, optical computing, quantum photonics, and dispersion control. The paper emphasizes the challenges and solutions for realizing and controlling these chips, focusing on waveguide loss, fabrication tolerance, power consumption, and control methods. It highlights the development of high-performance building blocks, such as ultra-low-loss silicon photonic waveguides, 2×2 Mach-Zehnder switches (MZSs), and microring resonator (MRR) switches. The paper also discusses methods for configuring large-scale programmable silicon photonic chips and summarizes representative examples for applications like beam steering, optical switching, optical computing, quantum photonic processing, and optical dispersion control. Finally, it provides an outlook on the challenges of further developing large-scale programmable silicon photonic chips. The paper reviews the progress in silicon photonic waveguides, which are crucial for low-loss signal processing. It discusses various methods to reduce waveguide loss, including improved fabrication processes and optimized mode field distributions. The paper also covers silicon photonic switches, including MZSs and MRRs, which are essential for optical signal processing. It discusses the performance requirements of optical switches, such as low losses, high extinction ratios, low power consumption, and low polarization sensitivity. The paper highlights the development of low-phase-error MZSs and MRRs, which are important for reducing random phase errors and improving the performance of optical switches. The paper also discusses programming strategies for large-scale optical signal processors, including self-configuring methods and the use of low-phase-error tuning elements. It highlights the importance of efficient programming strategies for achieving high-performance optical signal processors. The paper reviews the development of large-scale delay line arrays for signal processing, including MRR-based delay lines and long-waveguide-based delay lines. It discusses the applications of these delay lines in microwave photonic beamforming and optical signal processing. The paper also discusses large-scale optical switch arrays, including TO switches, EO switches, and MEMS switches. It highlights the advantages of these switches, such as low crosstalk, high extinction ratios, and low power consumption. The paper discusses the development of large-scale feedforward/backward optical signal processors, which offer more functional flexibility and convenient incorporation of tuning elements for microwave signal processing. It highlights the use of mesh-based computing processors, which allow the independent amplitude and phase control of photonic signals and can be configured to perform arbitrary unitary transformations on input vectors of coherent light modes. The paper concludes with an outlook on the challenges of further developing large-scale programmable silicon photonic chips, emphasizing the need for further improvements in waveguide loss, fabrication tolerance, power consumption, and control methods. It highlights the importance of these improvements for achieving high-performance optical signal processors and their applications in various fields.