Web services enable seamless application integration over the network regardless of programming language or operation system. A critical factor to the overall utility of web services is an efficient discovery mechanism, but the existing web services discovery is processed in centralized approaches such as UDDI, which has the limitations of single point of failure and performance bottleneck. In this paper, we propose a decentralized web services discovery mechanism (DWSDM) based on a distributed hash table (DHT) to solve these problems. DWSDM leverages DHT as a rendezvous mechanism between multiple registry centers. Besides, the proposed layered architecture which decouples application tier for registry center and overlay tier for network topology could facilitate system implementation quickly. Experimental results on the prototype implementation based on improved Chord algorithm show that DWSDM achieves insignificant improvements on both robustness and scalability.