The effect of combining nitrogen fertilization of base and topdressing with biologicalorganic fertilizer on the growth,dry matter,yield formation and its constituent elements og winter wheat variety Linyou 7287 was studied under maize straw returning to field.Results showed that comparing chemical fertilizer treatment,combined with biologicalorganic fertilizer significantly increased the area of leaves,dry matter accumulation and its contribution to grain,then led to higher yield.In the condition of 4 500 kg·hm-2 of biologicalorganic fertilizers application,the best ratio of base and topdressing was MN1∶1(ie50% as base fertilizer and 50% as topdressing)to improve yield,and the spike number,kernel per ear,1 000kernel weight and yield were improved by 12.71%,4.93%,6.42%,and 11.27%,respectively.So in Linfen basin of Shanxi,the most approriate combiningbiol ogicalorganic fertilizer with chemical fertilizer applying regime recommended was treatment MN1∶1,which was applied 4 500 kg·hm-2 of biologicalorganic fertilizers,combined with 225 kg·hm-2 chemical fertilizer,50% as base fertilizer and 50% as topdressing.