In print quality inspection, measuring results from different model of measuring instruments are quite different. A three-dimensional fitting algorithm was put forward to solve this problem. Forward and backward models were established. Measured value of i1Pro and SpectroEye, which were both commonly used in enterprises, were used predict each other. The color difference between the predicted value and the actual measured value was calculated. The experimental results showed that 98% of the color difference is less than 2, indicating that the algorithm has good result.