Semiliquid material packaging bag

The utility model relates to a packaging bag for fluid material. The utility model is characterized in that a bag mouth is provided with a control valve (1) of return flow. The control valve is a rectangular hollow cavity. A mouth of the hollow cavity is shrunk by a closing-in line (2) to form the shape that the upper mouth is large and the lower mouth is small. The control valve is combined with the box mouth at the inlet point in a hot pressing way. The utility model draws a conclusion that the simple valve body structure still has reliable performance through repeated experiments. The utility model has the advantages that material is saved, process is simplified, and thus production cost is reduced. The closing-in line of the utility model cause the fluid to have a buffering function when enters the bag mouth. The sealing performance of the bag is enhanced because the lower mouth is smaller that the upper mouth.