Nut leadscrew type automatic door opening and closing mechanism, automobile automatic door and automobile

A nut leadscrew type automatic door opening and closing mechanism for moving a door of a motor vehicle relative to a vehicle body. The nut leadscrew type automatic door opening and closing mechanism includes a driving device, a leadscrew, a nut pushing block and a pushing rod. The driving device is fixedly connected to a door, the leadscrew is rotatably mounted on the door, the nut pushing block is sleeved on the leadscrew, a first end of the pushing rod is hinged to the nut pushing block, and a second end of the pushing rod is hinged to the vehicle body. The driving device is capable of driving the leadscrew to rotate, so as to allow the nut pushing block and the pushing rod to be reciprocally linearly movable along the leadscrew to allow the pushing rod to drive the door to open or close relative to the vehicle body.