An implantable drug delivery device, comprising a check valve, a locking device, a drug delivery device body capable of being connected to a well-matched catheter through a locking device, wherein the drug delivery device body further comprising a pump frame, a well-matched punctured diaphragm disposed on the top of the pump frame, a pump cover well-matched with pump frame and punctured diaphragm disposed on the top of the punctured diaphragm, the pump cover, punctured diaphragm and pump frame sealingly connected to each other and a check valve connected to the pump frame, wherein a pump cavity is formed by the pump cover, punctured diaphragm, pump frame and the check valve forming a pump cavity.