Abstract: Source-sink relationship is a crucial problem to understand the physiological course of yield formation of crop,so does to maize.It's well known that source-sink relationship of maize was affected by many facts,such as cultivars,plant density and ecological conditions,and it had been classified into three types: source-limited,sink-limited and source-sink interacted.But the research related to effect of nitrogen fertilizer(NF),especially the different types of NF,on source-sink was seldom.In this study,two summer maize cultivars,Zhengdan 958(ZD958) and Nongda 108(ND108),were used as the material to study the effects of different N application rates(0,90 and 180 kg/ha) of three types of NFs,i.e.common urea(U),coated urea(CU) and compound fertilizer(CF),on source-sink relationship for yield formation of summer maize.The main results were as follows: 1) N application significantly increased the yield of summer maize,and the effect compound fertilizer was the highest.Grain number per ear of two cultivars increased along with the increment of N application rate,and the heightening value of Nongda 108 was bigger.The change of 1000grain weight showed difference according to cultivars and types of NF.2) LAI,chlorophyll content in filling stage and amount of dry matter accumulation of two cultivars increased with the increment of N application rates,and the heightening value of coated urea and compound fertilizer were bigger than that of common urea.3) Output percent of stem-sheath store matter can be used to reflect the harmonious degree between source and sink.In this study,it declined evidently with the increment of N application for two cultivars.The ratio of grain number to leaf area of Zhengdan 958 descended clearly after N application,especially application of compound fertilizer,but that of Nongda108 showed no evident trend.4) In a(general) way,positive correlation at 0.05 level existed between LAI,chlorophyll content and yield and grain number per ear (respectively,) but negative correlation existed between output percent of stem-sheath store matter and yield and its components.Negative correlation at 0.05 level existed between the ratio of grain number to leaf area and yield for Zhengdan 958, but this correlation for Nongda108 was weak.In conclusion,under conditions of this experiment,compound fertilizer and coated urea were more advantageous to heighten sink volume and source productivity than common urea,and as for type of source-sink relationship,Zhengdan 958 belonged to the source-limited and Nongda108 belonged to source-sink interacted.