The invention discloses a bottom door open and close device of a railway hopper car. The device can discharge goods on a receiving facility between the railways; the bottom door does not exceed the clearance of rolling stock under the opening state and can realize simultaneous travelling and discharging. The structure thereof is as follows: the device comprises a left bottom door, a right bottom door, a transmission shaft, a left locking body, a right locking body, a long ejector rod, a short ejector rod and a double lever; wherein, the left bottom door and the right bottom door are distributed at the bottom of the car body along the longitudinal center of the car in a symmetrical mode; simultaneously the left bottom door and the left locking body are fixedly connected on the car body and the right bottom door and the right locking body are fixedly connected on the car body; the transmission shaft is fixedly connected with the car body by a bearing seat and is then connected with a power device; the tail end of the long ejector rod is connected with one end of the double lever, the other end of the double lever is connected with the short ejector rod; the other end of the long ejector rod is connected with the left bottom door; and the other end of the short ejector rod is connected with the right bottom door.