Abstract: Based on electrostatic theory, the air target direction finding method using votary vane 3D electrostatic detector is studied in this paper. Three-channel signals detected by 3D electrostatic detector can provide the azimuth angle and elevation angle of the target in real-time. Analysis of relationship between leaf number of inductive electrode and inductive current amplitude was given. The finite element analysis software, ANSYS, was used to design and simulate the structure of detecting electrodes. The quantity of induced charge on detection electrode was simulated for different vanes. The effect of edge effect was also analyzed. The calculation result gives the optimum designing parameters of electrostatic detector, which provides a basic guidance for electrode design of rotary vane 3D electrostatic detector.