An improved rotor position estimation method of permanent magnet synchronous motor (PMSM) using Halleffect sensors was proposed. According to the Newton interpolation method, the curve fitting of discrete locations provided by Hall sensors was made. The realtime position information of the motor rotor was estimated in the algorithm for position fitting and interpolating. This method promised to eliminate the step position of the rotor position estimation and provided stable and reliable rotor position information, so that the stability of the closedloop system was improved. The simulation based on the simulation platform of Plecs was built. Compared with the traditional estimation method of rotor position, the results illustrated the effectiveness of the proposed method.