The utility model relates to the industrial automatic detection and control field and concretely refers to a component dimension detection system. The component dimension detection system comprises a singlechip controller; a PLC (Programmable Logic Controller) in connection with the singlechip and used for realizing automatic control; a LED light source in connection with the singlechip controller and used for realizing energy saving trigger; a computer host in connection with the singlechip controller through a serial port and used for realizing data transmission exchange; an industrial camera in connection with the computer host through a USB interface and controlled by the computer host; and a photoelectric sensor in connection with the industrial camera and used for detecting product passing information. The component dimension detection system can rapidly and stably detect component dimension and accurately drive peripheral equipment motion. For users, the system is simple and convenient to operate, has wide practical values, realizes component dimension accurate detection and raises work efficiency and product quality.