The performance of sensor is affected by the shape and the geometric parameters of coil. In order to optimize the detection performance of sensor, finite element model was established in the COMSOL Multiphysics. Simulation analysis on the structural optimization of sensor was conducted, and verified by the experiments. The biorthogonal rectangular sensor was found to have higher detection sensitivity comparing with the single orthogonal rectangular sensor. Otherwise, the effects of thickness, external shape coefficient, internal shape coefficient, excitation current, external shape proportionality coefficient of the auxiliary coil on detection sensitivity of sensor were investigated under the case of a fixed coil turn density. The conclusions from the study provide a reference for the determining of the coil parameters and the improvement of the sensor performance.