Abstract: A color monitor photo control system having a controller and a rectangular cone-shaped shield to prevent outside light from shining on the screen. The shield has a photo-sensor provided adjacent to the camera to sense brightness of the screen, and a light-testing button provided adjacent to the photo-sensor. The camera has a switching line connected to the controller and mounted on the shutter of the camera to actuate the controller and mechanically open the shutter. The controller is electrically connected to a color monitor and a computer. The controller has a micro-processor, and a number of RGB visual signal switches. The micro-processor receives signals from the light-testing button, the two-step switching line and the photo-sensor to adjust the number of frames of the RGB visual signals to the color monitor during the opening of the shutter with the aid of the visual signal switches.