The invention provides a high-gas mine Y-shaped ventilation method. The method comprises the following steps of: before the crossheading tunneling, tunneling a floor suction roadway in a coal seam floor rock layer, wherein the position of the floor suction roadway corresponds to a working face rail crossheading and open-off cut; arranging a gas drainage pipe in a roadway; tunneling the rail crossheading and open-off cut in a working coal seam right above the floor suction roadway to form a ventilation system; excavating a coal roadway along the coal seam strike at the tail end of the rail crossheading; tunneling an air return inclined roadway in an inclined downward direction along the coal seam at the tail end of the coal roadway; communicating the floor suction roadway after the same seam position of the floor suction roadway is reached; then, building a sealing wall at the floor suction roadway in the communicating position; and building a roadway-side filling body to remain a rail roadway in the working face extraction process, and arranging a gas drainage pipeline for draining gas in a goaf. The method solves the problem of gas bursting in the working face corner gas accumulation and tunneling process; the safety is high; one roadway has multiple purposes; the mining cost is low; the working face does not pass through an abandoned roadway; and the process is simple.