The estimating of Site index and site quality are fundamental theory and basic tools in forest ecosystem management and silviculture practice. The study on the spatial pattern and temporal dynamics of Site index and quality of forest ecosystem are still lack as the limitation of technology. It is a new approach of forest productivity estimating in large area using satellite remote sensed data. The Site index spatial distribution pattern of spruce (Picea asperata) forest was descript through the remote sensing vegetation index application and inverse models establishment in Northwest Sichuan Province, Songpan-Zhengjiangguan watershed, and evaluated the potential of methodology in broadly regions and forests through the accuracy assessment. The results show that Site index of spruce forest is linear correlation with remote sensed vegetation indices (Normalized Difference Vegetation Index (NDVI) and soil adjust NDVI (TNDVI)), as well as these inverse models with high accuracy. This study demonstrated that this approach can be used in similar estimating of different forest ecosystems.