Abstract: In order to improve fertilizer utilization rate and soil fertility in black soil area,the field experiment was set as follows.Conventional fertilizer application(slow-release fertilizer,N∶P₂O₅∶K₂O=29∶10∶13,600 kg·hm^-2)was used as control（CK）,and four treatments with increasing straw organic fertilizer and decreasing chemical fertilizer（T1,T2,T3 and T4）were set to analyze the agronomic traits of plants,leaf SPAD value,yield and fertilizer partial factor productivity,and to evaluate the effects of increasing straw organic fertilizer and decreasing chemical fertilizer on plant growth and yield formation of maize.Compared with CK,maize yield increased by 10.6%after straw organic fertilizer+20%chemical fertilizer reduction（T2）,while maize yield did not reduce after straw organic fertilizer+30% and 50% chemical fertilizer reduction（T3 and T4）.The SPAD value of leaves increased after T2,T3 and T4 treatments,and the plant height and yield components remained the same.Compared with CK,after straw organic fertilizer+foliar fertilizer treatment（T1）,maize leaf became etiolating,meanwhile SPAD value,ear length and row number of grains decreased,so as to yield reduced by46.9%significantly.The nitrogen partial factor productivity of T2,T3 and T4 treatments increased by 38.4%,41.6% and 100.5%respectively.Under the condition of this experiment,without the use of chemical fertilizer,only relying on straw organic fertilizer and foliar fertilizer could not meet the fertilizer required level of maize,which resulted in serious yield reduction.Chemical fertilizer reduced by 20%-50% combined with increasing straw organic fertilizer could achieve stable yield and improve fertilizer partial factor productivity.