The invention belongs to the technical field of optics, and provides a display control system and a display device. The display control system of the invention comprises a control unit used for making a light source alternately in a bright field and in a dark field in the same frame of data and making the state switching of the light valve of a spatial light modulator in the dark field time of the light source. The display device of the invention comprises the display control system. According to the system and the device of the invention, the control unit controls the bright field and the dark field of the light source to make the light valve of the spatial light modulator have a long switching time, and therefore, the switching speed of the light valve is increased, the difficulty in manufacturing the spatial light modulator is reduced, and the light source modulation accuracy of the spatial light modulator is improved.