The invention relates to a gas-insulated totally-enclosed switchgear gas leakage detection method. The method is mainly technically characterized in that an infrared imaging leakage detector is arranged opposite to a detection background, and a low-emissivity device is arranged between the detection background and the infrared imaging leakage detector and near the detection background; and the infrared imaging leakage detector is used for detecting detected space, and gas leakage is judged if smoke shadow appears. The design is reasonable, leakage detection on an SF6 gas of the gas-insulated totally-enclosed switchgear can be effectively carried out, problems that the existing gas-insulated totally-enclosed switchgear is low in gas leakage detection efficiency, the time is long, the defect discovery rate is low and the like can be solved, the leakage detection can be effectively carried out in an indoor environment, the working efficiency is greatly improved, the detection work risks are reduced, the safety of a worker is enhanced, and environment disruption brought by SF gas leakage can be effectively avoided.