On the basis of analyzing the temporal and spatial distribution of cotton leaf inclination angle, the ellipsoidal function was used to simulate the dynamic distribution of cotton leaf inclination angle. Cotton growth period was divided into four phases, and cotton canopy was divided into five layers according to Gauss distance. The model simulated the leaf inclination angle density distribution of different highness during different growth period that it can reflect leaf inclination angle distribution accurately. The model was validated by experimental data of different sowing dates. The coefficient of determination (R2) based on the 1∶1 line and the root mean square error between the simulated and measured values are 0.945 and 6.3% respectively. It proved that simulation results of the model come very close to the actual values.