本文引入了线性有源网络所伴随的混合图的主子图的概念,并提出分析线性有源网络用的一种新的拓朴方法,称为主子图法。该法是完全树法和有向树法的改革和统一。它解决了符号计算问题和对消项问题。它的符号计算比完全树法的简单得多。它没有对消项,这一点优于有向树法。 In this paper, we introduce the concept of the main subgraph of the hybrid graph which is associated with the linear active network, and propose a new topology method for the analysis of the linear active network, called the main subgraph method. The law is a complete tree and directed tree reform and reunification. It solves the problem of symbolic computation and elimination. Its symbolic computation is much simpler than the complete tree method. It does not eliminate the elimination, which is better than the directed tree method.