Since spot welding robots in welding processes usually have to traverse many solder joints, a key technology is how to plan the welding robot path. For the case that the number of solder joints reaches a certain quantity, it is difficult to use traditional methods to find an optimal path for spot welding robot. There are many indicators in welding robot path planning, such as shortest path distance, minimal welding time. Basing on the shortest distance, this paper proposes an improved partition PSO algorithm for welding robot path planning. The simulation results show the feasibility of the proposed method.