The invention provides an automatic LCD screen defect detection system. The system comprises two display screen movement assemblies, a camera movement assembly, an electrical control system, a computer, an alarm and a displayer, wherein the two display screen movement assemblies are arranged in parallel; each display screen movement assembly comprises a detection station and a mounting station; the camera movement assembly is horizontally arranged above the two display screen movement assemblies; when one display screen movement assembly drives an LCD screen to move to the corresponding detection station, the electrical control system controls the camera movement assembly to drive a camera to move to the corresponding detection station, meanwhile, the electrical control system controls the other display screen movement assembly to move to the corresponding mounting station, the camera acquires image information of the LCD screen and sends the information to the computer for image processing, and if the display screen has defects, the displayer displays corresponding defects, and the alarm gives an alarm. A conventional human eye detection mode can be replaced by means of the automatic LCD screen defect detection system, the human cost can be saved, and the problems of misjudgment and leak detection caused by human eye detection can be solved.