With the development of distributed computing, service-based software system which is constructed mainly by self-management Web services has become the main trend of software structure. The structure and behavior of service-based software system are continuously changed with user demands. Aiming at complex execution behaviors of web services, this paper presents an evolution model of dynamic behavior based on service interaction characteristics. Based on the WSDL documents of Web services, this model first builds complex structural network for the development evaluation of service-oriented software system. Taking into consideration of the optimal selection of Web services, characters of combination interaction and dynamic recombination, this work models the growth evolution and dynamic behavior of service-based software systems. Experiments are performed on large-scale real Web service data sets, such as Seekda and QWS. Different from hierarchical topological structure of traditional software system, the results show that the software systems consisted of self-management Web service exhibit more modularity structure. Compared with the regulation of single Web service evolution in the system, such as preferential attachments and dynamic recombination, the property of service structure network has more significant influence to the final form of the system. This model is instructive and meaningful to the analysis and management of service software.