Abstract: In order to intensively study the formation process of crater in short electric arc milling(SEAM) and reveal the material removal mechanism in SEAM from the micro point of view, the molecular dynamics model of nickel in SEAM was established to simulate the formation process of crater and lattice change zone under different discharge energy, and the experimental research was carried out. The results show that the depth to diameter ratio and depth of the crater and lattice change zone increase first and then decrease during discharge, and with the increase of discharge energy, the diameter and depth of discharge crater and lattice change zone increase.