The article reviews recent progress in large-scale programmable silicon photonic chips for signal processing, highlighting their applications in microwave photonics, optical communications, optical computing, quantum photonics, and dispersion control. Key advancements include the development of ultra-low-loss silicon photonic waveguides, 2 × 2 Mach–Zehnder switches, and microring resonator switches. The challenges of waveguide loss, fabrication tolerance, power consumption, and control methods are discussed, along with solutions such as broadened waveguides and self-configuring algorithms. Representative examples of applications, including beam steering, optical switching, optical computing, quantum photonic processing, and optical dispersion control, are summarized. The article concludes with an outlook on the future challenges and potential of large-scale programmable silicon photonic chips.The article reviews recent progress in large-scale programmable silicon photonic chips for signal processing, highlighting their applications in microwave photonics, optical communications, optical computing, quantum photonics, and dispersion control. Key advancements include the development of ultra-low-loss silicon photonic waveguides, 2 × 2 Mach–Zehnder switches, and microring resonator switches. The challenges of waveguide loss, fabrication tolerance, power consumption, and control methods are discussed, along with solutions such as broadened waveguides and self-configuring algorithms. Representative examples of applications, including beam steering, optical switching, optical computing, quantum photonic processing, and optical dispersion control, are summarized. The article concludes with an outlook on the future challenges and potential of large-scale programmable silicon photonic chips.