The modeling and optimization of distribution network fault diagnosis and repair process has been researched, based on the extended WF-net. Firstly, information systems were encapsulated into the loosely-coupled IT services. Secondly, the time set and color set of WF-net were extended, then the Timed Colored WF-net with IT Services (TCWFN-ITS) was put forth to explicitly demonstrate the calling relationship between business processes and IT services. Finally, this paper illustrates with a power company's distribution network fault diagnosis and repair process, employs TCWFN-ITS for modeling, and applies Petri net tool-CPN Tools for simulation analysis to enhance the performance of business processes and balance the calling of IT services, and verify the feasibility and effectiveness of the proposed approach.