The invention discloses a fast vacuumizing method for a non-sealed structure. The fast vacuumizing method for the non-sealed structure comprises steps of measuring a shape and a size of a non-sealed member, manufacturing a flexible film which is matched with the non-sealed member in contour, making an opening on the flexible film and installing a pipe connection port, pasting a ring of putty on acircumference of the non-sealed member, placing a matched ventilated felt in an area which is circled by the sealing putty, adhering the flexible film on the sealing putty, connecting the pipe connection port to a vacuumized device through a suction pipe and starting the vacuumized device to realize vacuumization on a selected zone. The fast vacuumizing method for the non-sealed structure can perform vacuumizing on the non-sealed structure members and components of various shapes, is low in cost and applicable to members of various shapes. The flexible film is adopted to replace cover boxes ofvarious shapes. The fast vacuumizing method for the non-sealed structure is short in production cycle, good in flexibility and can fast respond to the change of components.