Infrared thermal imaging technology uses spectral wavelength filtering technology to visualize the invisible VOCs (volatile organic compounds) that cannot be seen by naked eyes. It is a real-time non-contact measurement method, which can detect the gas leakage in dangerous areas or areas that are difficult to get access, so as to ensure the safety of inspection personnel. It has high sensitivity, and is suitable for the detection scene with low gas concentration and slow gas flow rate. It can timely find the gas that pollutes the environment or is harmful to personnel assets, and timely avoid profitable gas loss. It has great application value in safety production, environmental protection supervision and cost saving.