Quantitative anti-reflux drainage bag

A quantitative anti-backflow drainage bag comprises a liquid collecting bag, a drainage tube fixed at the top of the liquid collecting bag and a liquid outlet tube fixed at the bottom of the liquid collecting bag, and a lower port of the drainage tube is a one-way multi-valve port capable of preventing liquid from flowing back. The quantitative drainage assembly is in butt joint with the lower end of the drainage tube, liquid flows into the liquid collection bag through the drainage tube and the quantitative drainage assembly, and the quantitative drainage assembly floats upwards to be closed under the buoyancy of the liquid to limit the drainage tube to continuously guide the liquid into the liquid collection bag. According to the quantitative drainage bag, the liquid suction amount of the drainage bag is limited, the quantitative drainage assembly is arranged at the position corresponding to the 600ml volume or the 1000ml volume of the drainage bag, quantitative liquid suction of the drainage bag within the