In this paper, a MEMS surface resonant magnetometer based on Lorentz force is presented. This magnetometer has three current carriers to sense the magnetic field and changes into deflection of beams which will be detected by the comb-capacitance. The alternating current carried by oscillate beams has the same frequency as resonant frequency of the magnetometer structure to make the deflection magnified Q (Quality-factor) times, therefore, it becomes more easily to measure. In this paper, the mechanical model of the sensitive element is established. The equations of stiffness of the system, deflection, first-order resonance frequency and sensitivity are setup and simulated in ANSYS, as well as second-order to fourth-order modal, and harmonic excitation response simulation. It can be seen that the simulation results are in good accordance with the theoretical calculations, which proves the feasibility and the rationality of the theoretical model. The dimensions of the structure are designed, as well as the processing sequence Anodic Silicon-Glass Bonding and Silicon DRIE Multi-user Bulk Micromachining Process which will be used to manufacture the magnetometer. The MEMS surface resonant magnetometer has a high sensitivity, simple structure and easy to manufacture. The prototype sensors are being manufactured in NEDI now.