Abstract: As the basis of the high-level abstraction of the software system and subsequent development, testing and maintenance, the complexity of SA has a far-reaching impact on the system. According to the characteristics of CN and SA, the measurement and control method of SA complexity by using CN is proposed. This paper first introduces the method of complex networks and undirected and unweighted network, on this basis, the measurement of SA complexity is proposed through the degree of component, degree distribution of component, clustering efficient of SA, average path length of SA, modularity of SA, etc, then the complexity control method of SA and the reference range of the specific measurement attribute value are also given. Finally, the measurement method and control method of the SA complexity are verified by an example. The results shows that this method can metric and control the complexity of software system well based on strict formalization, and provides support and reference for subsequent development and maintenance of SA.