In modern enterprise, utilization of various systems for management purposes has become a common practice. When more and more systems are introduced to an enterprise, integration of these systems becomes more difficult due to the heterogeneous environment. In this thesis, application of Web Service based on XML (eXtensible Markup Language) technique is studied for solving integration problems in heterogeneous environment of power transformer manufacture. The automation of shop test procedure of transformer is used as an example to demonstrate the capability of Web Service technique. Through out the sharing databases and Web Service technique, system integration can be achieved among different departments.