The invention discloses a one-way pipeline film purifying device for drinking water. A water pump (1) is in serial connection with a water purifier (5) by water distribution pipes (2). The purifying device is characterized in that: an inlet and an outlet of the water purifier (5) are connected with a pressure difference sensor (6) by a pressure measuring pipe (4); electric valves (3) are respectively connected on the water distribution pipes (2) of the inlet and the outlet of the water purifier (5) in series; the signal output end of the pressure difference sensor (6) is connected with the input end of a controller (7), and the output end of the controller (7) is connected with the electric valves (3); and the controller (7) monitors the working condition of the water purifier (5) according to pressure difference between the two ends of the water purifier (5). The technology can be operated by a special cleaning company for off-line cleaning, detecting and maintaining on the one-way pipeline film purifying device, so as to make sure that the quality of water supplied at the end reaches the standard.