This paper studied the color transformation model of printing quality Inspection. The color space conversion models between RGB and CIEL*a*b* based on the three-dimensional look-up table and the polynomial regression algorithm were built using the test data of target color． Then the experiment was designed to compare the accuracy of the two algorithms. The maximum average color difference of the three-dimensional look-up table model reached 3，and the tetrahedron algorithm accuracy was slightly higher than the other three methods, the average color difference reached 0.64． Polynomial regression algorithm accuracy improved with the increase of the number of items, and the average color difference of the 20 items was 2.58. The accuracy of the three-dimensional look-up table model was higher than that of the polynomial regression model, and it had high precision and good effect. It was proved that the three-dimensional look-up table method could determine whether there was color cast in the printing image acquired by CCD, and the conversion accuracy of this method increased as the RGB color space was divided finer.