Negative pressure drainage bag with elastic sheet type opening structure

The utility model belongs to the technical field of medical instruments, and particularly relates to a negative pressure drainage bag with an elastic piece type opening structure. A negative pressure drainage bag of an elastic piece type opening structure comprises a main body bag, a plurality of anti-backflow heads are arranged on the upper edge of the main body bag, and a liquid outlet is formed in the lower edge of the main body bag. An adjuster is arranged in the main body bag and comprises an upper movable cover plate and a lower movable cover plate, buckling columns are arranged at the two ends of the upper movable cover plate, buckling hooks are arranged at the two ends of the lower movable cover plate, and the buckling hooks and the buckling columns on the same side are correspondingly buckled; an upper elastic piece is arranged on the inner side of the upper movable cover plate and is in an arc shape, the middle point of the back arch side of the upper elastic piece is fixed to the upper movable cove