In order to solve the problems of local minimum and unreachable target in traditional artificial potential field method, an artificial magnetic field method is proposed. Firstly, an artificial magnetic field is established around the obstacle, and the Lorentz force is introduced. The Lorentz force is perpendicular to gravity, so as to avoid the robot falling into the local minimum point; Secondly, the distance factor between the robot and the target point is introduced into the Lorentz force function to solve the problem of target inaccessibility; Thirdly, the direction of Lorentz force is optimized by establishing a virtual line between the target point and the obstacle, avoiding detours and reducing the number of steps of path planning. Finally, the traditional artificial potential field method and artificial magnetic field method are simulated in the MATLAB environment. The experimental results show that the artificial magnetic field method can overcome the local minimum problem and the target unreachable problem, and the planned path effectively avoids obstacles, preventing situations of oscillation and hesitation, thus improving the quality of path planning.