Because of the temperature changing， the image quality of IR cameras becomes worse. In order to prevent temperature-influence， a new mechanism of temperature-influence prevention is provided in this paper. It is based on lever principle to amplify the D-vale of different metals’ swelling value， and drive the lens to prevent the temperature-influence for IR optical system. The design programme， the parts’ key-design technology， and the design example of a guidance head are introdued. From -45~+60 ℃， the example’s drift value is 0.717， but it becomes 0 after temperature-influence is prevented. The experiments show that it is a new way for infrared athermalization.