Abstract: Photonics are increasingly used in space missions to promote performance of space burn system. The radiation issues for photonics are significantly different from those of Si digital microelectronics. It has been found that displacement damage effect is one of the most important damages for photonics used in space radiation environment and a few spacecraft anomalies have been attributed to displacement damage. So displacement damage have been studied seriously in recent year. In this paper, firstly the mechanism for displacement damage is introduced and the ways displacement damage affecting the performances of photonics are discussed; then displacement damage dose model which based on non-ionization energy loss is presented to predict the degradation of CTE in CCD, dark current in Si device and output power in solar cell. Finally, a program based on DDD model for CTE decline prediction in space environment is introduced. The difference between our prediction result with that of ESA SPace ENVironment Information System (SPENVIS) is less than 10%. In addition to that, the program can be used to evaluate the effect o shield for sensitive device and to convert the proton spectrum for a particular mission to a equivalent fluence at a specific proton energy. The study results will find widely applications in satellite radiation-harden design.