Electrostatic field mapping is an important part of university physics experiment, but the electrostatic field mapping instrument used has disadvantages such as large inherent error, low efficiency of manual point finding and vulnerable data processing. The mouse and microcrystal conductive plate were designed and developed to map the electrostatic field. During the experiment, the pen mouse and Geogebra software are used to locate and record the coordinates of the medium potential point of the electrostatic field, and origin data is used to process and visualize the electrostatic field. This design reduces the system error, improves the efficiency of finding points, and improves the operability of the experiment; uses software to process the experimental data, avoids the error caused by hand-drawn isopotential lines, and increases the rigor of the experiment.