Abstract: On the basis of Web service relational structure, this paper proposes an algorithm called ServiceRank to compute the service weight and rank the services In ServiceRank, by analyzing the relationship among the subsequent composable Web services, each Web service averagely distributes its weight by connectivity to all the subsequent composable Web services, and captures weight from all the predecessor composable Web services through the similar method. Compared with the current methods, ServiceRank has the ability to compute the unified weight function and to work offline. This paper thoroughly analyzes the convergence and stability of SercviceRank through experiments, which proves that the proposed algorithm has a high stability and efficiency.