Abstract: In order to increase the drainage concentration and efficiency of pressure relief gas in goaf, a design scheme of evaluation system for pressure relief gas drainage in goaf was proposed. The system collected data through sensors such as downhole gas concentration, wind speed and temperature, and uploaded data to the system to realize visual display and real-time monitoring of data. According to the technology of gas drainage in goaf and related theory, a three-level index system for evaluating the effect of gas drainage in goaf was established. Through comprehensive evaluation of gas drainage effect in Tingnan Coal Mine, the evaluation index R of pressure relief gas drainage in goaf was calculated to be 0.67, which reached the standard of "good".