In order to make small infrared camera carried by a flight equipment can be well in a wide temperature range and bad dynamic environment, opto-mechanical structure of camera was designed. Firstly, the optical system and working environment were analyzed, according to design experience of the similar products, all-aluminum body were used for the opto-mechanical structure; Secondly, the core component-primary mirror support structure was studied in detail. By reason of limitations of traditional primary mirror support structure, integrative design was used for primary mirror support structure. this design was equally applicable to secondary mirror. Thirdly, thin-wall canister was used for the support structure between primary and secondary mirrors according to size of camera. And then，rational baffle was designed according to the optical system. Lastly, overload adaptability, temperature adaptability and modes of camera were analyzed. Results show that opto-mechanical structure of small infrared camera meets design requirements.