The invention discloses a rotor-position sensor doubly salient motor system and a control method thereof, belonging to the field of doubly salient motor systems and the control method thereof. The system consists of a doubly salient motor, an excitation winding, a main power circuit and a control circuit, wherein, the main power circuit comprises a power supply and an IPM; and the control circuit comprises an isolation circuit, a failure detection circuit, a three-phase current sampling circuit, an excitation current sampling circuit, a PWM control circuit, an over-current and over-voltage protection circuit, an ADC module, a position detecting circuit, a rotation speed calculation circuit, a logic control circuit, a capture unit, a speed loop, a current loop, a hysteresis comparator and a PI regulator. The control method indirectly controls the current of the doubly salient motor by adopting a dual-loop control type of internal loop for current and external loop for rotation speed and comparing the given rotation speed for reference with the fed practical rotation speed. The method has simple system, firmer structure, reliable operation and high efficiency.