The invention discloses a high-efficiency denitrification activity sand filter system. The high-efficiency denitrification activity sand filter system comprises a denitrification activity sand filter basin, wherein the denitrification activity sand filter basin is sequentially provided with a front filter area, a biological reaction area, a rear filter area and a filter material washing area from bottom to top; a central pipe longitudinally penetrates through the front filter area, the biological reaction area and the rear filter area; the upper end of the central pipe is connected with a water inlet pipe; a water distributor is arranged on the lower end of the central pipe; the filter material washing area is provided with a water outlet pipe; a cone is arranged at the lower part of the front filter area; a blow-down pipe and an overhauling opening are arranged on the lower end of the cone; a quartz sand casting bed is arranged in the front filter area; the biological reaction area is provided with a biological carrier box; a sand distributor is arranged in the cone; the filter material washing area is provided with a sand washer and a sewage tank; the sewage tank is provided with a sand washing water outlet pipe; the lower part of the sand distributor is connected with the upper part of the sand washer through a sand lifting pipe which penetrates through the central pipe. The high-efficiency denitrification activity sand filter system disclosed by the invention integrates filtration and denitrification biological treatment into a whole and has the advantages that a filter bed is shallow, no complicated back washing system is provided, the manufacturing cost is low, the total nitrogen removing efficiency is high, and a process control system is simple and convenient; the utilization rate of a device is increased.