Abstract: In order to study the influence factors of transmission performance of magnetic coupling of magnetic pump, the design model was numerically calculated based on Ansoft-Maxwell software, and the influence of the model on the transmission performance of magnetic rotor under different magnetic steel gap was qualitatively analyzed. Taking the magnetic torque and magnetic eddy current loss as the evaluation indexes, 4-26 pairs of magnetic blocks with different arrangement were designed respectively, and the magnetic field distribution of magnetic rotor was analyzed. The peak value of the magnetic torque, the average value of the eddy current loss and the resultant force（F） of the inner and outer magnetic blocks were obtained. It is concluded that the magnetic torque and eddy loss of the model reach the optimal value at 16 pairs. Taking 16 pairs of log-pole magnetic rotors as an example, the influence law of clearance size on transmission torque and magnetic vortex loss was investigated under the condition of changing the clearance degree of adjacent magnetic steel: 1°, 2°, 3° and 4°, respectively. The results show that increasing the magnetic steel clearance will reduce the magnetic torque and magnetic eddy current loss slightly, but when the matrix A3 steel is added in the middle of the clearance and other conditions remain unchanged, the magnetic eddy current loss will increase by about 1.2 times. The results can provide a useful reference for the parametric design of magnetic rotor of magnetic pump.