The utility model provides an automatic cut and keep off rubbish curb drainage system, including the novel drainage curb that is located the rivers updrift side, be located rivers low reaches direction cut to keep off rubbish drainage curb, cut the detachable arc leaf grating for down pipe that keeps off rubbish drainage curb and include the second curb body, be located second curb body below, the internal convex draw -in groove of establishing of second curb sets up the built -in fitting on the convex draw -in groove, and a plurality of second atmospheric pressure balancing holes have been seted up on the second curb body to the installation and the dismantlement of the arc leaf grating for down pipe of being convenient for, have seted up a plurality of second wash ports on the arc leaf grating for down pipe, the outside arch of arc leaf grating for down pipe, and it is unanimous with the internal outside protruding angle of convex draw -in groove of establishing of second curb. The utility model relates to an automatic cut and keep off rubbish curb drainage system can solve the wash port that blocks the drainage curb because of rubbish, and the problem of the drainage inefficiency that leads to, thereby the drainage efficiency of curb has been improved greatly.