The device is used to detect the tightness of lamps and lanterns of automobiles. The device includes a frame, a transmission cylinder, an upper template, an operation table, a fixed cylinder, a tool, an inflatable device and a control system. The transmission cylinder is arranged on the frame, and the upper template is fixed. At the end of the cylinder rod of the transmission cylinder, the fixed cylinder is set on the upper mold plate, and the tooling is divided into an upper mold and a lower mold. The fixed cylinder is used to fix the upper mold, the operating table is used to place the lower mold, and the inflation device is set on the lower mold to control the The system includes a PLC module and a detection element connected with it, a driving cylinder solenoid valve, an air charging solenoid valve, a fixed cylinder solenoid valve, a delay relay, a working time relay, a detection time relay, a pressure regulating valve, a control button and a display device. The invention realizes Semi-automatic, so as to achieve the purpose of rapid detection, prevent defects in the products that leave the factory, improve work efficiency, and ensure production quality.