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In order to explore the effect of returning whole straw associated with combined cow manure and reduced chemical fertilizer application on grain yield, uptake and use of nitrogen under rice-wheat rotation system in Tai Lake region, an experiment was laid out with randomized design with four replicates of five treatments, respectively, CK(non-fertilization), CF(inorganic fertilizer that N application was 240 kg·hm-2), OMCF(70%CF with 3 000 kg·hm-2 cow manure), CF+S(CF+returning whole straw)and OMCF+S(OMCF+returning whole straw). Each plot was 46 m2 in area and isolated by plastic waterproof membrane to prevent the water and nutrients exchange between plots. The soil in ploughed layer before the experiment contained 21.5 g•kg-1 soil organic matter, 2.30 g·kg-1 total nitrogen, 0.93 g·kg-1 total phosphorus, 140 mg·kg-1 available nitrogen, 39.0 mg·kg-1 available phosphorus, 74.3 mg·kg-1 available potassium and pH 7.6. The grain yield and yield component, accumulation, distribution and translocation of nitrogen and dry matter aboveground, N use efficiency and amount of soil mineral nitrogen at each treatment were measured/calculated for comparison. The results showed that change rule of grain yield in treatments as follows:OMCF+S, CF+S, OMCF, CF, CK, application of organic fertilizer promoted sink capacity and thousand seed weight. Application of returning whole straw associated with combined cow manure and reduced chemical fertilizer promoted dry matter accumulation and nitrogen uptake, and also increased the distribution of dry matter and N to the grain at mature, which was beneficial for the transformation from biological yield to economic yield. It also improved assimilation of dry matter at filling stage and translocation of N in vagetative, and thereby promoted nitrogen use efficiency. The increment of OMCF+S treatment's nitrogen use efficiency was more obvious than OMCF or CF+S separately as a result of cooperative action of returning whole straw and cow manure. The increased content of soil mineral nitrogen at mid-late growth stage by application of returning whole straw or cow manure, especially OMCF+S, improved nutritional conditions at mid-late growth stage of crop, improved young spike differentiation and grain-filling, and laid a foundation for increment of grain yield. Conclusions: Cooperative action of straw returning and combined application of cow manure and chemical fertilizer improved the coordination of yield component at a higher level, and higher yield was obtained, meanwhile, it improved N use efficiency by the realization of self-regulation of crop-soil. [ABSTRACT FROM AUTHOR]