Abstract: The effects of nitrogen application on dynamic changes of starch and its compositions and ratio of amylopection to amylose in grains of spring maize (high starch maize SIDAN19, common maize NEAU250, good quality protein maize FENGHE10) were studies in field experiment. The results showed that contents of amylopectin, amylose and total starch went up in spring maize grains after spinning. The highest total starch content was found at the level of N200 in grains for all tested varieties, the highest amylopectin contents of SIDAN19 and FENGHE10 were found at the level of N200 in grains, SIDAN19 was the best tested variety at this aspect of total starch and amylopectin contents. The amylose content of FENGHE10 increased with the raise of nitrogen application, but the highest amylose content of SIDAN19 was found at the level of N200. The ratio of amylopectin to amylose fell gradually after spinning.