Abstract: Plastic fuel tank is storage equipment for automobiles,and the performance of fire resistance is directly related to the lives of drivers and passengers. Therefore,the fire resistance performance test of automobile plastic fuel tank is a mandatory item that must be inspected by the state. According to the in-depth analysis of the requirements of the national standard GB 18296-2019,a testing device suitable for the fire resistance test of plastic fuel tank with different capacities of30-90 L is designed. The preparation work before the device is tested adopts the manual mode to simulate the fuel tank installation in the real vehicle. The all-automatic unattended mode is strictly implemented in the test process,and the remote control and the video monitoring is combined to ensure the safety of the detection process. The modular design concept is introduced in the paper,and the mechanical structure of the fire resistance testing device for the fuel tank is divided into four modules according to the functional elements. Each module is based on the ergonomics concept,and carries out innovative design according to the design requirements. The key parts of the testing device are analyzed by finite element analysis to verify the strength of the testing device and to ensure the reliability of the testing device. The fire resistance testing device for automobile plastic fuel tank designed in the paper meets the requirements of national standard and achieves the expected design effect,which provides a reference for the design of similar products.