The invention discloses ventilation and drainage equipment for a gearbox. The ventilation and drainage equipment comprises a hollow box boy, an exhaust pipe arranged on the first side portion of the box body and used for connecting a ventilation opening of the gearbox, an upper drainage pipe arranged on the second side portion of the box body, a lower drainage pipe arranged at the lowest positionof the bottom of the box body, and at least one water blocking plates arranged in the box body. The joint of the upper drainage pipe and the box body is lower than the joint of the exhaust pipe and the box body, and the water blocking plates are used for slowing the flow rate of water from the lower drainage pipe into the box body to the upper drainage pipe. An ventilation pipe is used for connecting the gearbox and an externally-connected ventilation box body, the exhaust pipe and the upper drainage pipe are arranged in a falling mode, the water blocking plates are arranged, the effects of dust prevention, water blocking, water draining and air exhausting can be increased, and the rate of inflow pollution at the ventilation opening of the gearbox is reduced.