Web service composition is to integrate component services for providing a value-added new service. With the growing number of component services and their dynamic nature, the centralized composition model can't manage them efficiently and accurately. In this paper, we proposed a distributed hash table (DHT)-based peer-to-peer (P2P) service composition framework, called ServiceStore. Compared with the central control in centralized model, in our ServiceStore, service selection and composition are distributed to the involved task brokers, requesting nodes and service nodes. Furthermore, a simple parallel service selection approach which can still satisfy global constraints is proposed and implemented in our multi-role cooperation (MRC) protocol. The results of experimental evaluation show that ServiceStore can achieve high scalability and efficiency.