An infrared gun scope was usually exposed to high-frequency and high-intensity stress concussion,and some dependability malfunctions may happen if the corresponding methods wasn’t used during the designing. Based on the ANSYS software,a finite element simulation had been done to one infrared gun scope,whose simulation emphasis was the transient analysis. According to the analysis data,malfunction of the infrared gun scope had been found out,and some effective measures had been used to resolve the problem. In the end ,this product had been optimized and satisfied with the environmental condition.