A flow stopper preventing the backflow of urine, comprising a urinary tube connector (10), a flow stopping valve (20), and a urinary bag connector (30). The flow stopping valve (20) is a membrane material. A flow channel (201) runs through the front and rear ends of the flow stopping valve (20). The flow channel (201) is provided with a front-end inlet (202) and a rear-end outlet (203). The front-end inlet (202) is in communication with a valve port (13) of the urinary tube connector (10). The rear-end outlet (203) is a flat slit. A channel (301) of the front and rear end surfaces of the urinary bag connector (30) is provided with a front-end port (302) and a rear-end port (303) connected to a urinary bag tube. The flow stopping valve (20) is arranged within the channel (301). Moreover, the rear-end outlet (203) of the flow channel (201) is directly opposite to the rear-end port (303) of the channel (301). With the employment of the membrane material serving as the flow stopping valve (20), and the rear-end outlet (203) of the flow channel (201) being a flat slit, when urine flows through the rear-end outlet (203), due to the extendibility of the membrane, the urine is drained when the urine opens up the rear-end outlet (203)； and when the urine is fully drained from the rear-end outlet (203), the rear-end outlet (203) closes due to the extendibility of the membrane, thus preventing the backflow of the urine, and preventing a patient from being infected. Moreover, this is structurally simple, convenient, and practical and, compared with a conventional flow stopper, automatically prevents the backflow of urine.L'invention concerne un bouchon d'écoulement empêchant le reflux d'urine, comprenant un raccord de tube urinaire (10), une valve d'arrêt d'écoulement (20) et un raccord de poche urinaire (30). La valve d'arrêt d'écoulement (20) est un matériau de membrane. Un canal d'écoulement (201) s'étend à travers les extrémités avant et arrière de la valve d'arrêt d'écoule
