High-speed space communication networks urgently require optical modules featuring high bandwidth，low latency，and miniaturization.In this paper，the displacement damage effect，single-event effect （SEE），and temperature characteristics of optical modules are investigated，aiming to elucidate the degradation patterns and underlying mechanisms of the key parameters of the optical modules in the space environment.Through the environmental tests，it is found that the incident neutrons introduce displacement damage defects in the vertical-cavity surface-emitting laser （VCSEL） and positive-intrinsic-negative （PIN） detector of the optical module，reducing the minority carrier lifetime and thus decreasing the optical output power and receiver sensitivity.The optical module is susceptible to the SEE.The heavy ions cause bit-flips in the registers within the driver circuits，resulting in communication bit-errors and communication interruptions.The threshold current of the VCSEL increases with temperature，which is the main reason for the degradation in the optical output power of the transmitter module.