The invention discloses a sample introduction adapter device of a gas detector and an application method thereof, and belongs to the technical field of gas detecting. The sample introduction adapter device of the gas detector comprises a first interface used for being connected with GIS equipment, a second interface connected with a pressure gauge, and third interfaces connected to the detector. The first interface, the second interface and the third interfaces are all communicated with one another through pipelines, and the number of the third interfaces is at least two. According to the sample introduction adapter device of the gas detector and the application method thereof, multiple available interfaces are provided, multiple detectors can be allowed to conduct detecting at the same time, the testing time is shortened on one aspect, and the labor intensity of testing personnel is greatly lightened; on the other aspect, testing results are closer to the inside condition of a GIS air chamber.