Abstract: Combined the similarity criterion with Darcy Law, similar criterion numbers of gas migration laws were reduced in the goaf of fully mechanized caving face in coal seam. The goaf in No.2306 fully mechanized caving face of Zhangcun Coal Mine was taken as the prototype, the similar model was built. Under the condition of U, U+L and U+I ventilation patterns with different wind speed, the experimental study had been carried out about the gas migration in goaf and the change of gas concentration in the upper corner. The results showed that the ventilation patterns determined the space change laws of gas migration in goaf; the wind speed determined the fluctuation degree and influence scope; the U+I ventilation pattern was the most effective way to reduce the gas ventilation in the upper corner; the gas concentration control effect was the best for wind speed from 1.5 m/s to 2.5 m/s, the lower the wind speed was, the more easily the gas accumulation occurred, the high gas migration fluctuated obviously.