Main structure of product family can be depicted as a directed complex network. Parameters such as node betweenness, edge betweenness and Q function values were calculated through simplepath detecting algorithm for obtaining distributing curve of Q and clustering dendrogram. Division results can be gained from clustering dendrogram. The results were adjusted and optimized according to parts usage times and entities with sign. As an example, a product family of the industry steam turbine was analyzed with this algorithm and some practical results were obtained.