When the switched reluctance motor (SRM) is running, the increased current caused by the increased load will lead the SRM to the magnetic saturation status. The traditional sensorless control method to solve the problem of magnetic saturation for SRM requires a lot of off-line measurements. So, a sensorless control strategy of SRM based on special position judgment is proposed, which obtains the full cycle inductance by injecting high frequency pulse voltage into the non-conducting phase. The unsaturated phase inductance values corresponding to four special positions at 15°, 30°, 45° and 60° are obtained on-line through the linear variation relationship of the unsaturated section of the inductance curve. According to the inductance-angle function, four special positions are obtained in one cycle. The motor speed and the full cycle rotor position are estimated by two adjacent positions. On this basis, a simulation model based on Simulink and an experimental platform with DSP are built, with which the correctness of the proposed method is verified.