At present, there are problems such as mechanical vibration and rigid friction in low speed and high torque transmission system. According to the modulated magnetic gear effect, the field-modulated permanent magnet gear motor (FPGM) can be used for low speed and high torque direct drive. By analyzing the role of each harmonic of winding magnetomotive force in FPGM and fractional slot concentrated winding permanent magnet synchronous motor (FSCW-PMSM), the similarities and differences between the two motors are qualitatively compared. By establishing the finite element model of FPGM and FSCW-PMSM, the differences of torque characteristics, power factors and parameter characteristics are analyzed, and the ability of FPGM to produce large torque is verified, which provides a reference for the analysis and design of key parameters. The no-load experimental platform of FPGM prototype is built, and the experimental data are compared with the finite element analysis results, proving the feasibility of using FPGM to provide low speed and large torque scheme.