Abstract: The paper discussed the methodology of automatically extracting vegetation factors by studying the correlation between conventional forest resources inventory method and new method invented by remote sensing since it can not be acquired via visual interpretation directory, after the forest resources inventory by SPOT5 satellite image. The verification results of the forest factors depicted by the new method and site inventory are, 86% correct for young forest, 92% correct for shrub and 96% for grass. The new methodology improved the efficiency of forest inventory. It has profound mean in promotion of forest inventory to understand the forest resources.