For flux-weakening control of electric vehicles, this paper adopts a method of single current regulator to solve the strong coupling problem between d-axis and q-axis. This method utilizes switching between MTPA and flux-weakening control in different operation state. In flux-weakening operation, the d-axis voltage is gotten by d-axis voltage regulator. While the q-axis voltage is gotten by a regulator directly. The new flux-weakening control strategy can fully utilize the DC voltage and make the motor working at the optimal operating point. To verify the feasibility of the control strategy, a Matlab/Simulink modeling is established. Finally, Infineon TC1782 as the main control chip is used to build the drive system platform of electric vehicle to test the actual application ability of the proposed control strategy.