Abstract: In order to master the air distribution law of goaf with Y type ventilation, according to the site actual condition, a physicalmodel of goaf with one intake an d two air retuning Y type ventilation was established.The Fluent software was applied to the numerical simulation study on the air leakage flow field of goaf with one inta ke and two returning Y type ventilation, the air leakage quantity and the gas concentration distribution. The results showed that with the lower corner distance increased, the air leakage from the coal mining face to the goaf would reduce and the air leakage quantity near the upper corner would seriously increase .Along the length of the g oaf, the gas concentration would be higher when more closely to the goaf in deep mine . Along the direction of the coal mining face, the gas concentration near the side of the transportation gateway would be low and the gas concentration near the side of the goaf would be high.