A two-dimensional (2D) Dirac semimetal with coexisting superconductivity has been long sought but rarely reported. Light-element materials, such as boron, are considered promising candidates due to their intrinsic lightweight and metallicity. This study investigates a newly synthesized β₁₂-hydrogenated borophene, β₁₂-B₅H₃, which is a scarce Dirac semimetal with strain-tunable phase transitions from three Dirac cones to a single Dirac cone. It is also a superior phonon-mediated superconductor with a critical temperature (Tc) of 32.4 K, which can be increased to 42 K under external strain. The coexistence of Dirac fermions and superconductivity, along with dual tunabilities, makes β₁₂-B₅H₃ an attractive platform for studying quantum phase transitions in 2D Dirac semimetals or the exotic physics arising from their interplay. β₁₂-B₅H₃ is a stable 2D material with good mechanical properties, as confirmed by first-principles calculations. It exhibits three clean Dirac cones near the Fermi level, which can be tuned into a single Dirac cone under external strain. The material also shows high superconducting properties, with Tc of 32.4 K and potential enhancement to 42 K under strain. The phonon density of states and electron-phonon coupling calculations indicate that β₁₂-B₅H₃ is a promising phonon-mediated superconductor. The study also reveals that the superconducting properties of β₁₂-B₅H₃ can be influenced by strain, with Tc increasing under certain conditions. The material's unique combination of Dirac semimetal and superconducting properties makes it a valuable platform for exploring exotic quantum phenomena.A two-dimensional (2D) Dirac semimetal with coexisting superconductivity has been long sought but rarely reported. Light-element materials, such as boron, are considered promising candidates due to their intrinsic lightweight and metallicity. This study investigates a newly synthesized β₁₂-hydrogenated borophene, β₁₂-B₅H₃, which is a scarce Dirac semimetal with strain-tunable phase transitions from three Dirac cones to a single Dirac cone. It is also a superior phonon-mediated superconductor with a critical temperature (Tc) of 32.4 K, which can be increased to 42 K under external strain. The coexistence of Dirac fermions and superconductivity, along with dual tunabilities, makes β₁₂-B₅H₃ an attractive platform for studying quantum phase transitions in 2D Dirac semimetals or the exotic physics arising from their interplay. β₁₂-B₅H₃ is a stable 2D material with good mechanical properties, as confirmed by first-principles calculations. It exhibits three clean Dirac cones near the Fermi level, which can be tuned into a single Dirac cone under external strain. The material also shows high superconducting properties, with Tc of 32.4 K and potential enhancement to 42 K under strain. The phonon density of states and electron-phonon coupling calculations indicate that β₁₂-B₅H₃ is a promising phonon-mediated superconductor. The study also reveals that the superconducting properties of β₁₂-B₅H₃ can be influenced by strain, with Tc increasing under certain conditions. The material's unique combination of Dirac semimetal and superconducting properties makes it a valuable platform for exploring exotic quantum phenomena.