The invention discloses a sewage impurity filtering device, which comprises support legs. A filtered sewage output pipe and a filtrate discharge pipe are located on the support legs; a filter disc isconnected to the upper parts of the filtered sewage output pipe and the filtrate discharge pipe, and one side of the filter disc is connected to a sewage input device; a rotary column is vertically installed at the center of the filter disc; filter screens in different directions are uniformly dispersed at the edge of the rotary column; a tilted filter screen impurity cleaning apparatus is arranged at the lower part at the inner wall of the filter disc; a pressure discharge switch is installed in the filtered sewage output pipe; and a transmission apparatus connected to the pressure dischargeswitch and the rotary column is arranged at the rear outer wall of the filter disc. The problem that large impurity is left in sewage and blocks the filter screens is overcome, the sewage filtering efficiency is increased, and sewage and large impurity are automatically separated. The impurity left on the filter screens doesn't need manual cleaning. The sewage impurity filtering device is convenient for people, simple in structure and convenient to use.