Abstract: In order to clarify the variation of different nitrogen fertilizer levels, stem number and plant height of different rice （Oryza sativa L. ）varieties, a randomized block experiment of different nitrogen fertilizer levels and early construction was set up. The results showed that under the different nitrogen fertilizer levels, the results of the two varieties of Hemeizhan and Yuenongsimiao were consistent for the early cropping and late cropping. The results showed that the number of stems and plant height increased with the increase of nitrogen application rate. In the tillering stage and the jointing stage,there was a extremely significant positive correlation between early cropping and late cropping nitrogen application rate and stem number, and a significant positive correlation or extremely positive correlation between booting stage and yellow maturity stage. Early cropping and late cropping nitrogen application and natural plant height, physiological strain there was a significant positive correlation or extremely positive correlation between the tillering and the booting stages and a extremely significant positive correlation between the jointing stage and the yellow maturity.

Key words: rice （Oryza sativa L. ）, nitrogen fertilizer, number of stems and tillers, plant height, correlation