The invention discloses a posterior cranial distraction and drainage device used in the neurosurgery department. The posterior cranial distraction and drainage device comprises a base, wherein a waste fluid collecting box, a supporting rod, a cleaning liquid storage box and a power supply are respectively arranged at the top end of the base, the supporting rod is distributed in the middle of the top end of the base, the waste fluid collecting box, the cleaning liquid storage box and the power supply are all distributed on the side face of the supporting rod, the waste fluid collecting box and the cleaning liquid storage box are arranged in a bilateral symmetry mode, the power supply is distributed on the front side of the waste fluid collecting box and the cleaning liquid storage box, and a mounting support is arranged at the top end of the supporting rod. The posterior cranial distraction and drainage device ensures that the cleaning liquid temperature is always in a normal temperature state through a temperature sensor and a heater, provides a comfortable treating environment for a patient, makes the drainage process easy to control through a flow control valve, ensures that the drainage amount is always in a normal range, relieves the pain of the patient in operation and brings convenience to medical workers in work.