In order to study the effects of irrigation and drainage modes and nitrogen level on rice plant height and tiller growth dynamics, the water level in the paddy field was taken as the control index in the leaching-pond. Logistic curve and DMOR mathematical model were used to quantitatively analyze the effects of drought and flood alternating stress in tillering (FHL) and the drought and flood alternating stress in jointing-booting (BHL) stage and controlled irrigation and drainage treatment (CID) at different nitrogen levels on plant height and tiller dynamics. The results showed that the irrigation and drainage modes promoted the plant height and tillers mainly by changing the growth time and increasing growth rate of plant height and tillers. The maximum of plant height was shown as BHL, FHL and CID in descending order and the maximum number of tillers was shown as FHL, BHL and CID in descending order. Nitrogen fertilizer application promoted the plant height and tillers mainly by increasing growth rate of plant height and tillers. The maximum of plant height was increased with the increase of nitrogen application rate, from 98.9cm and 97.8cm with 150kg/hm2 input to 102.4cm and 101.2cm with 300kg/hm2 input, and no further significant increase was observed with more nitrogen input. Under the treatment of CID and BHL, maximum number of tillers was increased with the increase of nitrogen application rate. Under the treatment of FHL, the maximum tiller number under low nitrogen treatment and high nitrogen treatment was less than that under medium nitrogen treatment. The interaction between irrigation and drainage mode and nitrogen level had a very significant impact on the dynamic process of plant height and tillering. The decrease of plant height and tiller number caused by water stress could be alleviated by increasing nitrogen fertilizer to some extent. However, high nitrogen level can aggravate water stress, which was not conducive to the growth of plant height and tillers.