In the Color Management System, monitors play an important role. During the digital workflow, people are used to checking files on displays. The realization of soft proofing will not only increase flexibility, but also reduce producing time and materials. This paper describes the theory of display color management and soft proofing. A method is proposed about using CRT display to simulate the printing color effect on paper and using LCD display to simulate the displaying effect on CRT. And the experimental results are analyzed and assessed.