With PFEM（probabilistic finite element method）

the probabilistic finite element model of a pair of small gears manufactured with LIGA method is established.The finite element model is verified through comparing the result of FEM with the result of Hertz theory.The influence of the material characteristics parameters and the load to the performance of the gear system is studied when these parameters greed with normal distribution.The basis is supported for the manufacturing and heat treatment of the gear system so as to ensure the reliability of the gear system.