This paper presents detailed analysis of the DFIG-based wind energy conversion system(WECS) under three-phase voltage dips conditions via a coupled simulation. 1.5MW DFIG is modeled in Ansoft-Maxwell, and the simulation is coupled with Ansoft-Simplorer and Matlab-Simulink for drive circuit and controller implementation. The coupled simulation system including DFIG, RSC, GSC, DC-Link, step up transformer, VSG and the control algorithm, which is very comprehensive to get a more clear performance analysis of DFIG under voltage dips. The finite element model of DFIG is designed more closed to the wind generator in practical application. The simulation result perfectly matches those obtained theoretically and validate the analysis.