Novel medical drainage bag

The utility model relates to the technical field of medical drainage bags, and discloses a novel medical drainage bag which comprises a bag body, a flow guide tube is detachably arranged at the upper end of the bag body, a liquid inlet is fixedly formed in the upper end of the bag body, and a liquid inlet tube is fixedly arranged in the middle of the upper end of the liquid inlet. A connecting sleeve is fixedly arranged at the upper end of the liquid inlet and located outside the liquid inlet pipe, a clamping ring is fixedly arranged at the upper end of the connecting sleeve, a clamping groove is formed in the inner wall of the flow guide pipe, a sealing plug is fixedly arranged on the inner wall of the flow guide pipe, a drainage pipe is fixedly arranged on one side of the lower end of the bag body, and the lower end of the drainage pipe is fixedly connected with an external pipe. A graduated scale is fixedly arranged at the front end of the external pipe, a liquid outlet head is fixedly arranged at the lowe