The invention discloses a rapid starting method of a low-temperature low C/N sewage improvement A2/O process, which belongs to the field of sewage treatment and resource utilization. The method comprises the following steps: firstly, selecting columnar polypropylene suspended filler and radial fiber filament suspended filler with cavity structures, respectively feeding into a front aerobiotic section zone 1 and a rear aerobiotic section zone 2 of a reactor, subsequently keeping the concentration of sludge inside the reactor be 1.8-2g/L, changing the ratio of the reaction zones and controlling sludge discharge by moving a partitioning plate, gradually culturing and enhancing nitrobacteria, denitrifying bacteria and phosphorus-accumulating bacteria inside the system, so as to successfully achieve low-temperature high-load starting. By feeding the suspended filler into different zones according to different types, reasonably utilizing a carbon source and optimizing the function of different reaction zones, the capability of nitrobacteria and phosphorus-accumulating bacteria in competing with oxygen in the aerobiotic zones is improved; the operation is controlled, various microorganism are rapidly enriched inside the system, and the pollutant removal rate is increased. The method disclosed by the invention is simple and feasible, rapid in starting speed, high in efficiency and wide in usability.