The invention discloses a tunnel circumferentially extension type waterstop fixed mold and a using method. The tunnel circumferentially extension type waterstop fixed mold comprises a steel plate, channel steel, a steel tube lead screw and reinforcing steel bar inserting holes. The tunnel circumferentially extension type waterstop fixed mold has the beneficial effects that the mold is matched with a secondary lining trolley pouring cement concrete to the positions of construction joints, a waterstop fixed clamp is placed between a rear waterstop and an intermediate waterstop, and a screw is rotated, so that the clamp is butted against the rear waterstop and the intermediate waterstop, straight mounting of the waterstop is maintained in the secondary lining concrete pouring process, and the waterproof effect of the secondary lining construction gap waterstop is improved.