The utility model relates to a bag-turning type filtering centrifuge which comprises a rotary drum which can be rotatablely supported in a machine shell. A filter bag is arranged in the rotary drum, and one end of a hollow main shaft which is driven by a motor is fixedly connected with the bottom of the rotary drum. A movable shaft rigidly passes through the main shaft, and is fixedly rotated with same velocity along the circumferential direction of the main shaft. The movable shaft can slide, corresponding to the main shaft, and the movable shaft is a hollow shaft. One end of the hollow movable shaft is connected with a movable sleeve by a bearing which can transfer the axial force. The centre of the movable sleeve has a threaded through hole which is matched with a rotary threaded shaft which is arranged in the through hole. The movable sleeve is pulled for the slide in the axial direction, and the axial movement is transmitted by the bearing to realize the separation of the axial movement and the circumferential direction movement. The threaded shaft can extend and contract in a cavity of the hollow movable shaft at the time of rotation, and the axial dimension of a bag-turning mechanism can be saved.