Live fuel moisture content (LFMC) is an important factor in wildfire risk assessment, but the estimation of LFMC is affected by the leaf area index (LAI) if it is retrieved using a radiative transfer model. To reduce the influence of LAI in the LFMC retrieval process, we used the interval estimated LAI to parameterize the PROSAIL ( ) radiative transfer model. The LAI values were first estimated based on the MODIS LAI product (MOD15A2) using a simple downscaling technique, and then were constrained using an interval estimation method at the confidence levels of 80%, 90%, and 95%. To evaluate the reliability of this approach, another two LAI constraint strategies were applied, weakly constrained LAI over a wide range and strongly constrained LAI with fixed values. A look up table (LUT) was set up for the parameterized PROSAIL model. Furthermore, the LFMC can be retrieved based on the Landsat TM and 8 products. The results showed that the retrieved LFMC using the interval estimated LAI at the 95% confidence level resulted in the best accuracy level ( , ), which was slightly better than the LFMC obtained when using the interval estimated LAI at confidence levels of 90% ( ) and 80% ( ). The accuracy levels of the retrieved LFMC using weakly constrained LAI ( ) and strongly constrained LAI ( ) were poor. Thus, this study demonstrated that LFMC retrieval could be improved by using the interval estimated LAI.