The work aims to solve the problems of color difference evaluation of complex color areas of packaging materials, complex criteria and poor consistency of results in visual inspection methods. In this paper, an RGB color space color difference evaluation method based on high-precision digital images of packaging materials was proposed. By setting up a high-precision digital image acquisition device, the full digital image of the standard sample of packaging materials (upper limit, middle limit and lower limit) was obtained. By using the method of RGB color space dimensionality reduction, the color space of the test area of the standard sample was fitted with discrete boundary, and the three-limit sample RGB color difference model of the test area of the standard sample was constructed, and the color space of the corresponding test area of the test sample was compared. The color difference qualification of the test sample was judged according to the consistency of the color space model. Compared with various discrete boundary fitting models, the inclusion rate and excess rate of the rolling ball method edge fitting model reached 100% and 78.9%, respectively, and the model fitting effect was the best. Through the verification test of color difference defect samples of packaging materials, the accuracy of the above color difference evaluation method reached 100%. The rolling sphere color space edge fitting model and color difference evaluation method proposed in this paper can realize the color difference qualification judgment of complex color areas of packaging materials, which is conducive to improving the intelligent detection level of enterprise production.