Abstract: A thermo-elastic-plastic finite element method is used to simulate the process of spot welding, which analyzes the effect of the welding current and squeezing force on the properties of spot welding , and shows the electrode displacement presenting the properties of spot welding .It is proved that the sound nugget can be achieved when the electrode displacement is controlled in an acceptable scope .Furthermore , a fuzzy control method is proposed that the welding current is modified in real time by monitoring electrode displacement.By using the fuzzy control method, the nugget size of spot welding is controlled in real time , and the properties of spot welding are acceptable.It is convenient to choose the initial welding parameters for achieving the sound resistance spot welding by using the fuzzy method proposed in this paper.