The invention relates to the field of cameras, and provides a camera automatic gain effect detection device, which is simple and convenient to operate and instantly reads images. The device comprises a box body, an adaptation board, a picture panel, a monitor, a plurality of controlled light sources and a backlight source, wherein the box body is a hollow accommodation chamber of which two ends are provided with an opening respectively; the picture panel is arranged on the opening on one side of the box body; the adaptation board is arranged on the opening on the other side of the box body; alight hole is formed on the adaptation board; a camera lens to be detected is arranged on the light hole of the adaptation board; the monitor is connected with the camera lens to be detected to acquire the shot images; each controlled light source is arranged between the picture panel and the camera lens to be detected on the inner side of the box body; and the backlight source is arranged in the vicinity of the other side, away from the camera lens to be detected, of the picture panel.