Abstract: In order to realize the automation of electric spark deposition (ESD), a closed loop control system of discharge parameters for ESD was developed. Discharge parameters during deposition are collected in real time. Based on the linear law that the average discharge pulse voltage is inversely proportional to the contact force, the closed-loop control of the average discharge pulse voltage is achieved by the feed motor and the feed slide adjusting the contact force between the workpiece and the electrode, and thus the automatic feed adjustment of electrode is realized. The analog circuit, digital control circuit and control software of the control system are designed by modular technology, which can shorten the development period, ensure the reliability and facilitate the upgrade and expansion. The test results of ESD show that the developed closed loop control system of discharge parameters can realize the stable contact between electrode and workpiece and obtain uniform and dense deposition layer, which is convenient to realize the automatic operation of ESD and is conducive to the popularization and application of ESD technology.