An effective system equivalent circuit model plays an important role in understanding system characteristics and improving system performance. However, most existing studies provided only final models, it’s unclear what factors and how these factors affect electrostatic tactile system exactly. Based on the custom-designed electrostatic tactile device, we analyzed completely the effects of ground connection method, human body grounding position, human impedance and insulator capacitance on system output performance in this paper. Analysis results show the output voltage under direct connection is six times larger than under nature connection, proving the necessity of direct ground connection. Furthermore, we also proved the negligible effects of human body grounding position and human impedance. Finally, we show larger permittivity and smaller thickness of insulator may cause better system performance. Based on these findings, we established a practical equivalent circuit model and analyzed system frequency characteristics and waveform characteristics.