Abstract: Distributed technology and object-oriented analysis method play an important role in virtual environment research, especially in complex application. In a practical virtual environment system, three problems should be considered: ①the expression of complex model, ②the behavior control of the user, and ③the network communication. From the system architecture’s point of view, there are three layers- algorithm layer, relationship layer, and behavior layer in a virtual environment system. A behavior-based object model is proposed in this paper according to the above analysis. This model is expressed using the traditional object-oriented method, and the communication primitives in CSP model are also embedded in it to solve the third problem in the virtual environment system. The model has been applied in the simulation of an autonomous robot architecture and has been proved to be efficient by the experiment result.