The evaluation of site index and site quality provides not only a fundamental theory but also basic tools for forest ecosystem management and silviculture practice. Site index is a well-received method of evaluating site quality, However, the traditional site index inventory method is very time consuming and cost, It is difficult to apply this method for spatial analysis in large area due to the limitation of technology. Geostatistics which combine with geographic information system provides a new approach for studying forest site index and its spatial pattern. In this study, the site index spatial distribution pattern of Chinese fir plantation forest was describled using geostatistics and geographic information system after choosing appropriate variogram model in Fengshushan Forest Farm in Jiangxi Province, We then evaluated the results through the accuracy assessment. The results show that site index of Chinese fir plantation forest has middle degree spatial correlation. After comparing the estimated results with actual results, the K-Bessel models are confirmed with high accuracy. This study indicates that this new evaluation approach can be used for site index spatial pattern analysis in different forest ecosystems.