Gas-solid two-phase flow is widely used in the transportation of materials in industrial production. The electrostatic method is widely used in the measurement of two-phase flow due to its disadvantages of low cost, easy detection, and strong adaptability. Based on the principle of electrostatic induction, the structure parameters (thickness of tube wall, electrode width, charge, position, etc.) of the sensor are set by finite element analysis method. The spatial sensitivity of the sensor is studied under different electrode width. The amplitude frequency characteristics of the sensor are studied and analyzed according to the static and dynamic characteristics of the electrostatic sensor. Simulation results show that: the electrostatic sensor has low-pass filtering characteristics in the spatial frequency domain; the closer the particles pass through the pipeline, the narrower the spatial frequency band; the faster the speed of those particles in the pipeline, the wider the frequency band of the sensor; the longer the axial length of the electrode, the greater the amplitude of the signal. When the electrode width is determined, the best sensing range of the electrode in the pipeline can be obtained.