Abstract: The study aims to illustrate the relationship between double cropping rice LAI and TEP, and the influence of nitrogen. Field experiments with eleven early and late rice cultivars and four nitrogen application rates were conducted, and LAI was measured at the main growth stages, normalization processing of LAI and accumulated TEP was conducted, simulation analysis of LAI (RLAI) and TEP (RTEP) was carried out with the software of Curve Expert, six simulation model with fine fitting results were obtained, and the rational equation could describe the dynamic change of LAI accurately, with the correlation index of 0.9677**, which had biological significance. Independent field test data were used to test the model, the results indicated that the root mean square error (RMSE) between the observed and simulated values of LAI at varied RTEP was 0.50 m2/m2, indicated that the RLAI dynamic model based on RTEP could reflect the dynamic change of double cropping rice LAI accurately. The LAImax showed the trend of quadratic equation with the increase of nitrogen application, the change of RLAI showed a“N”shape with the increase of RTEP. The results provided a theoretical upport to high yield cultivation and precise control of LAI of double cropping rice.