Web服务是一种崭新的Web应用。随着Web 环境下服务数量的快速增长，在海量的待选服务中发现所需的服务将十分耗时。UDDI V2 增加了一个新特征PublisherAssersion来描述UDDI注册中心中商业实体间的关系，类似于网页之间的超链接，由此可产生Web服务图。本文首先研究Web服务的新特征，然后提出与分析了Web服务图的构建原理和构建算法，最后利用Web服务图进行服务发现，提出了基于Web服务图的服务发现匹配算法，并对其进行了仿真实验。从仿真实验结果可以看出，本文提出的Web服务图对组合的Web服务发现是有效的。

Web services are a new kind of Web applications. As the services published on the Internet expand exponentially, finding them becomes more and more timeconsuming. UDDI v2 has added a new feature, publisherAssersion, to express the relation between business entities in a UDDI repository center just like a hyperlink between the Web pages. Thus, a Web service graph can be generated. This paper observes the new features of Web services first. The principles and an algorithm for constructing a Web service graph is proposed and analyzed in detail. Using the Web services graph for service discovery is elaborated then. Finally, it is shown from the simulated experiments that the Web services graph proposed in this paper is useful for composite Web service discovery.