Abstract: The Y-type ventilation is a better way to control the upper corner and gob gas, but the direct determination of air leakage field and gas flow field in gob is very difficult. This paper establishes a two-dimensional calculation model, the distribution of air leakage field and the gas concentration field in gob are studied by using CFD numerical simulation software, then a comprehensive comparison is carried out about different air volume distribution ratio between main and auxiliary air roadway.it obtained that gas control effect is the best when air volume distribution ratio is 5:1.