Abstract: In order to explore the optimal application rate of biochar for planting maize on saline alkali soil,a field plot experiment was conducted to study the effects of different application rates(0,10,20,40,80 t·ha^-1) of biochar on maize growth,nutrient accumulation,and yield.The results showed that,biochar increased the accumulation of dry matter after flowering,promoted the increase of grain filling rate,and enhanced the absorption of nutrients（C,N,P,K） by maize plants and grains,thereby increasing maize yield and improving maize quality.Therefore,in the alkaline maize field of the western Songnen Plain,the application amount of biochar of 40 t·ha^-1 is the most sufficient for nutrient accumulation in the leaves,stems,and sheaths of maize plants,with a long active period of grain filling and the highest maize yield,making it the most economically effective amount.