Unpowered sewage purification device achieving efficient denitrification and use method thereof

The invention discloses an unpowered sewage purification device achieving efficient denitrification and a use method thereof.The unpowered sewage purification device comprises three levels of treatment units.Each level of treatment unit comprises an anaerobic treatment region and a reaeration region, wherein the anaerobic treatment region and the reaeration region are separated through a partition plate, and a sewage overflow hole is formed in the tail end of the partition plate; a sewage inflow pipe is arranged at the front end of the bottom of the anaerobic treatment region of the first unit for connection, a water distribution branch pipe is arranged on the sewage inflow pipe located outside the device for water distribution, and the water distribution branch pipe enters the device through the anaerobic treatment region of the first level of treatment unit and the anaerobic treatment region of the second level of treatment unit; the reaeration region of each level of unit is provided with a sewage guide tube communicated with the anaerobic treatment region of the next level of treatment unit; the bottoms of the tail ends of the anaerobic treatment regions of the first level of unit and the second level of unit are provided with sludge overflow holes; a drain tube is arranged at the tail end of the reaeration region of the third level of treatment unit.No power is consumed, the microorganism concentration in the device is balanced through reasonable sludge distribution, and the removal effect of nitrogen containing pollutants in the sewage is improved.