Abstract: To study spatial distribution and seepage laws of methane in gob, a three-dimensional simulation testing system for methane seepage in gob was newly developed. Laying similar simulation materials into the main body of the system, uniformly loading the upper part of similar materials using loading system, the bottom plate lifting system was used to simulate the coal seam excavation, and methane was injected into the downward goaf formed by the gas supply system. The methane concentration in the three-dimensional goaf was detected by the gas extraction system arranged in similar materials. The test results show that the goaf is divided into the source flow area, the flow suppression area, the confluence area and the no-flow area from the bottom up; the coal bed gas concentration in the source flow area is the highest, flow suppression zone inhibits coalbed gas seepage in goaf and its concentration drops sharply, the coalbed gas concentration gradually rises in the confluence zone, however, the overall concentration of CBM is lower than that of source flow area, and there is no CBM in no-flow area. By carrying out the test of surface coalbed gas extraction in the old goaf area at Jinsheng Mine, an abandoned mine in Shanxi Province, the results show that the results are satisfactory when the ground drilling bottom is located in the source flow area.