Semantic feature modeling is a new trend of CAD technology. It is very important for modifying and editing models automatically and semi-automatically. In this paper, a semantic feature modeling method is proposed, in which geometric constraints of models are solved. The new method is history-independent. At the same time, the architecture of semantic feature modeling is given. According to the principles of 3 dimensional rigid bodies, basic geometric constraints can be expressed. Experiment results show an instance modeled by the proposed method.