According to the testing principle of gas direct pressure method, combined with the structural characteristics of cable pipe hole, this research designs and develops a set of device suitable for cable pipe hole airtightness testing, which has the characteristics of easy operation, portability, and visualization. In the process of testing, the self inspection mode, bubble mode and detection mode can be used to conveniently and effectively achieve accurate detection of the airtightness of cable pipe holes. At the same time, this study also takes the cable pipe hole of a 110 KV power tunnel in a city as an example, through the test of the cable pipe hole at the project site, it analyzes that the cable pipe hole 1,#, and 2,#, have leakage risks, effectively verifies the applicability and feasibility of the airtight detection device, which can provide a certain technical reference for the development of similar projects in the future.