Abstract: To explore the degradation and mechanism of 850 nm high-speed vertical-cavity surface-emitting laser in space radiation environment, the degradation of light output power and threshold current were obtained by Gamma ray and 10 MeV proton irradiation. The physical mechanism of VCSEL parameter degradation caused by radiation was analyzed. In addition, 236 h forward-bias annealing research was also carried out. The results show that VCSEL is not sensitive to the total dose effect caused by gamma rays, the photoelectric properties have a certain degree of recovery due to the deposition energy promoting the order of the crystals near the quantum well interface within a certain dose range. But threshold current and external quantum efficiency of VCSEL are degraded in varying degrees under proton irradiation, the threshold current damage factor is calculated to be 1.468 × 10⁻¹⁵ cm²/p. After 20 mA forward-bias annealing, the threshold current is restored by 20%, and the optical output power is restored by 10% at 25 mA injection current. The degradation of threshold current and external quantum efficiency is attributed to the non-radiative recombination center introduced by proton irradiation. These results provide support for the application of VCSEL and the data communication and instrument system containing VCSEL in harsh space radiation environment.