By combining the field-weakening control principle of interior permanent magnet synchronous motor(IPMSM) with the space vector pulse width modulation(SVPWM) and MTPV control principle, a novel field-weakening control strategy for IPMSM was proposed. In the first phase of the field-weakening ,the difference between the reference voltage updated by current regulator and the saturated voltage output by SVPWM is used for field-weakening control, which modifies the stator current. This method makes full use of the DC bus voltage, and can naturally smooth transition; In the second phase of the field weakening, the principle of MTPV control is used for field-weakening control, and then linearized, Compared with the traditional method, this method solves the problem of depth weakening of IPMSM. Between the two stages, the turning speed is used for switch condition to achieve the smooth transition for the first stage to the second stage. The effectiveness of the proposed field-weakening control method and calculation method was verified with simulation results.