The invention discloses an oil immersion rust prevention device for motor stator machining. The oil immersion rust prevention device comprises an oil tank, an ejection plate, an air cylinder, an installing ring, a motor and a rotating shaft; and the oil immersion rust prevention device is characterized in that the oil tank is arranged on a support, a vertical plate is arranged on the top of the oil tank, the ejection plate is arranged on the vertical plate, the air cylinder is arranged on the vertical plate and is provided with a power line and a piston rod, the installing ring is arranged onthe piston rod through a fastening bolt, a fixing plate is arranged on the installing ring, the motor is arranged on the side wall of the oil tank, the power line is arranged on the motor, one end ofthe rotating shaft is arranged in a bearing, the other end of the rotating shaft is connected with the motor, and a stirring plate is arranged on the rotating shaft. By means of the oil immersion rustprevention device, a through groove is formed in the fixing plate, a bearing rod is vertically arranged on the fixing plate, liquid in the oil tank conveniently flows to the position above the fixingplate from the position below the fixing plate through the through groove, liquid oil can be in sufficient contact with a motor stator, and the oil immersion effect of the motor stator is improved.