The invention relates to a biology processing apparatus capable of processing sewage at low-temperature with low carbon-nitrogen-ratio in a cold region and a method for processing sewage at low-temperature with low carbon-nitrogen-ratio in the cold region, which relates to the biology processing apparatus for processing sewage and the method for processing sewage. According to the invention, problems that the ratio of carbon source and nitrogen source of sewage in winner at the cold region is low, the synchronization nitrogen and phosphorus removal efficiency in the current sewage processing technology is low, the index of nitrogen and phosphor in a processed effluent can not reach the standard can be solved. The apparatus comprises a water storage tank, a pre-conditioning hypoxia pool, an anaerobic pond, an anoxic pool, an aerobic tank, a sedimentation basin, an aeration head, a filling material, a stirrer, a water inlet pump, a reflux pump, a valve, an outlet pipe, a sludge discharge pipe and a residual sludge discharge pipe; The method comprises the following steps: 1)culturing microbe on a filling material; 2)adjusting operation parameter; 3)adjusting reflux ratio parameter; 4)passing the sewage through the pre-conditioning hypoxia pool, the anaerobic pond, the anoxic pool, the aerobic tank and the sedimentation basin for processing to obtain the processed water. The apparatus and the method can be used for construction and reconstruction of the sewage processing technology at low-temperature with low carbon-nitrogen-ratio in a north region.