The　characteristic　of　the　diaphragm　spring　has　great　influence　on　the　performance　of　the　clutch,　so　the　diaphragm　spring　optimization　design　is　very　important　in　the　clutch　design　work.　This　paper　deals　with　the　multi-optimization　of　diaphragm　spring　by　using　Particle　Swarm　Optimization　(PSO)　algorithm.　For　the　proposed　algorithm,　the　mathematics　model　is　established　and　optimizing　objectives　are　chosen　properly.　An　application　example　is　used　to　test　the　algorithm,　the　result　shows　that　the　diaphragm　spring　have　better　non-linearity　characteristic　after　optimum　design　with　this　method　compared　with　two　other　design　methods.