Self-control precision metering drainage bag

The utility model discloses a self-control precision metering drainage bag which comprises a metering box and a liquid storage container. The bottom of the metering box is provided with a sampling pipe. A rotary switch is arranged between the metering box and the sampling pipe. A metering notch is formed between the metering box and the rotary switch. A pipe wall opening is formed between the pipe wall and the rotary switch. The rotary switch is provided with a switch pipe. A pipe opening in one side of the switch pipe is provided with a groove opening. The self-control precision metering drainage bag is at least provided with a siphoning state, a sampling state and a liquid discharging state under the rotating state of the rotary switch. By means of the self-control precision metering drainage bag, the sampling pipe is arranged, the sampling operation can be conducted by controlling the rotary switch and is convenient and fast to conduct. The drainage bag is made to be provided with the adjustable siphoning state, the sampling state and the liquid discharging state through the rotary switch, selection and control are facilitated for medical staff. When the self-control precision metering drainage bag is in the liquid discharging state, the liquid in the metering box directly enters a liquid discharging pipe through the metering notch and the pipe wall opening without flowing through a siphoning pipe, no extra liquid discharging pipe needs to be additionally arranged, and cost is reduced.