Abstract: The present experimental device for surveying and mapping the electrostatic field by simulation method commonly uses conductive paper or conductive glass as conductive medium. The uneven distribution of the medium often affects the accuracy of experimental results and the probe is easy to wear medium surface to cause damage. Changing the probe position manually to determine the isopotential point is cumbersome and inaccurate. In order to overcome the disadvantages of the existing experimental device, an improved experimental device has been put forward. The device adopts sodium chloride solution with certain concentration as conductive medium to avoid conductivity fluctuations. The device uses the controller to drive the stepper motor and linear motor to move probe accurately and conveniently.