A stool drain assembly including a main tube, an integrated connector, a potion or feces flushing water hole, a low-pressure balloon expansion water hole, at least two liquid pipes and a low-pressure balloon is provided. The main tube has a tube wall, an injection end and a water outlet. The integrated connector is disposed at the injection end and has a potion or feces flushing water injection cavity and an expansion water injection cavity. The potion or feces flushing water hole and the low-pressure balloon expansion water hole are arranged at the water outlet and are connected to the inside and outside of the tube wall respectively. At least two liquid pipes include a low-pressure balloon expansion liquid delivery pipe and a potion or feces flushing water liquid delivery pipe.