Objective A monitor color reproduction model was established to realize the conversion from Lab to RGB, using a NEC monitor as example. Methods The model was based on the modified cube subdivision algorithm, which processed the points outside the color gamut. Through choosing an optimal subdivision level, the model could balance between the conversion calculation precision and algorithm efficiency, in this way, the color reproduction of the monitor was realized. Results The accuracy of the model was analyzed with the CIELab color difference formula, the average color difference during the model conversion was 1.8068, which was in the acceptable range of human vision. The largest color difference was only 4.6051. The model had high conversion precision. Conclusion The model established in this paper could realize the accurate conversion of the monitor from Lab to RGB.