The variation of fertilizer agronomic efficiency and partial productivity of spring maize in Northeast China wasanalyzed，and its variation mechanism was studied，which provided important theoretical basis for improving nitrogen useefficiency of spring maize in NortheastChina.The variation mechanism of partial productivity of nitrogenfertilizer(PFP N)and agronomic efficiency of nitrogen fertilizer(AE N)was studied by 921 field experiments of“3414”in Northeast Chinasince2010.AE N decreased with the increase of nitrogen application and Y0/YG(Y0 and YGare bisic yield and targetyield，respectively)，increased with the increase ofDY(Y G-Y0)，and decreased with the increase of F N/(1-Y 0/YG)；PFP N increased with the increase of Y0，decreased with the increase of fertilizerapplication，increased with the increase of Y 0， and increased significantly with the increase of Y0/FN.It was found that F N and Y0/YG were two variation pathways of nitrogenfertilizer agronomic useefficiency.Soil nitrogen supply intensity was the main factor affecting AE N，Y0 and FN were twovariation pathways of partial productivity of nitrogen fertilizer，and fertilizer nitrogen supply was the main factor affecting PFPN.