With the rapid development of information technology, the growth of heterogeneous Web data and the requirements of access to the Web of data also is growing. In view of this, a method of heterogeneous data integration based on SOA(Service-Oriented Architecture) is proposed. This method combines the technology of middleware and SOA design, using XML and Web services technologies, presents a framework of heterogeneous data integration based on SOA, and introduces the architecture of SOA data integration middleware. Experimental results show that this method reduces the coupling of heterogeneous data integration system effectively, and improves the scalability of the system.