The effect of robot spraying was unknown, so the thickness simulation of curved surface spraying was studied. The spray gun model was established, then the surface single point spraying thickness algorithm was written by using MATLAB, and the simulation program in the teaching path was programmed. A continuous curved surface model with continuous curvature was established by using SolidWorks, and the surface data were obtained. The surface spraying simulation experiment was carried out by using the simulation program. According to the result, the modification scheme is adjusted and simulated again, and the experimental results are consistent with the prediction.