Abstract: The effect of nitrogen on fat accumulation in different organs and fatty composition content in grain in two types of maize were studied. The result showed that the fat content in leaf and stem of two types of maize was tended to decrease during grain filling,and that in grain of two maize was changed differently. There were different effects of nitrogen levels on fat content in leaf and stem,and that in grain of two maize was increased with increasing the rate of nitrogen. Applying nitrogen affected mainly oleic acid and linoleic acid contents in fatty compositions of grain,and the contents of stearic acid,palmful acid,linenic acid in grain were insignificantly affected by nitrogen treatments.