Abstract: For solving the problem of the lack of the optimization evaluation rule of the micro-component, an approach by combining the FEM with the rough set theory is used to study the optimization decision rule of the micro-component in this paper. An abundant information data of the micro-component is produced through the FEM dynamic analysis. These data is mined by the rough set theory and the genetic algorithms, and then the reduced attribute and the optimization decision rule of the micro-component are obtained. Based on this approach, the prototype system of the optimization decision rule of the micro-component is developed and a thermal actuated micro-pump optimization decision rule is established as an application instance in the paper. The achievement can provide a new method and also a prototype software tool on the optimization decision rule establishment for the micro-component product design.