Evolutionary design is one kind of intelligently cooperative design, which is analogous to the evolutionary process of products. A forming method for the genome of 3D model in evolutionary design is proposed based on feature functions and topology functions. 3D model consists of features, which can respond to the environment by their functional faces and parameters, the genome which is represented by the features and their topology has been studied. The feature and topology functions are combined with geometry API in the CAD software. The genome which is symbolized as feature and topology functions is operated for the 3D model evolutionary design by genetic operators. So the genome can be taken out from the rich CAD model database to form enough scale initial population. At last, the test of phone models demonstrated the evolutionary design process including gaining their genomes automatically, evolutionary computation of their design and visualization, etc.