Pneumatic clamp is widely used in automobile welding fixture because of its advantages of convenient operation and low clean cost of power source. Gas path design is an important part of fixture design. The design of gas path system and pipeline layout have certain influence on the structure of welding fixture and the movement track of robot. In this paper,Taking the automobile exhaust system welding fixture as the background,the general steps of the gas circuit design are given,aiming at some problems encountered in the installation and commissioning of gas path components of the solution are put forward,and the corresponding optimization suggestions for gas circuit design are put forward.