Casing and fishing integrated device for drilling constant-pressure entrapment plugging tool fish

The invention relates to the technical field of underground fishing tools, and discloses a casing and fishing integrated device for drilling constant-pressure entrapment plugging tool fallen fish, which comprises an upper adapter connector, an upper casing milling barrel, a casing milling double-male adapter, a casing milling outer barrel and a lower casing milling barrel which are connected in sequence, an inner retreating slip assembly for fishing fishes is arranged in the casing milling double-male adapter, the casing milling outer cylinder and the lower casing milling cylinder; one end of the inner rollback slip assembly is matched with the inner wall of the milling double-male adapter, and the other end of the inner rollback slip assembly is matched with a fishing section of a fish; the end, away from the casing milling outer cylinder, of the lower casing milling cylinder is connected with a casing milling alloy head used for milling fishes. And a cutting tooth section is arranged between the setting rub