The utility model provides a multistage automatic negative-pressure oil exploitation tool, belonging to the technical field of oil exploitation equipment. The multistage automatic negative-pressure oil exploitation tool is characterized in that from bottom to top, a thread protector is connected with a liquid inlet floral tube; the liquid inlet floral tube is connected with a lower connection hoop; a one-way valve is combined with a center pipe in a welding manner; the lower connection hoop is connected with the center pipe; a lower isolation ring, a leather bowl and an upper isolation ring pass through the center pipe, and are fastened by a locking ring; and the center pipe is connected with an upper connection hoop. The multistage automatic negative-pressure oil exploitation tool has the beneficial effects that an oil layer is not damaged and the environment is not polluted by using a physical method to extract oil; simple machining and convenience in construction can be realized; less investment and quick effectiveness can be realized; the multistage automatic negative-pressure oil exploitation tool can automatically work undergrounds for a long term; the multistage automatic negative-pressure oil exploitation tool is suitable for being used in a national hypotonic oil field; and an oil layer can be prevented from being polluted and damaged through well washing liquid in an oil well washing process.