Abstract: Biological trickling filter (BTF) has the disadvantages of low removal efficiency of nitrogen and phosphorus, easy clogging of the filter, and bad smells. In order to achieve the effluent standards and improve the operational efficiency for different wastewater quality in rural areas, improvement researches have been made by domestic and foreign scholars. The structure of BTF can be improved by reducing the filter influent organic concentration, increasing the oxygen content, and removing nitrogen and phosphorus in different stages, etc. Water distribution can be improved by reducing the volume of water droplets, distributing water uniformly, and raising the water distribution height suitably. Different sorts of filter materials can be combined to have complementary advantages according to the characteristics of the wastewater. Through combining artificial inoculation film-forming with natural biofilm, biofilm can be adopted in the shorter time. Increase of the reflux ratio can improve the removal efficiency, with optimum reflux ratio is 60%-80%. The continuous improvement of the BFT makes it more advantageous in the treatment of wastewater in the rural areas.