This study aimed to investigate the method for accuracy prediction of color space conversion by general regression neural network. Through the modeling, testing data was collected by MeasureTool software of automatic measurement. The test was repeated for optimization of modeling right parameters. Finally, the simulation experiment was carried out using General regression neural network model, and a better RGB to Lab color space conversion model was obtained. Our results showed that the average color difference on testing General regression neural network model reached 2.5275, and the maximum color difference was 19.3620. In general, the established method is easy and convenient, which has good non-linear fitting capability and higher prediction accuracy in color space conversion.