Abstract: According to the species, age class and their combinations, the sub compartment was carried out using the data of forest inventory for management plan and ETM data in Boluo county of Guangdong province.In this paper, the correlativity between the volume of subcompartment and auxiliary factors, i.e.,subcompartment area, the product of subcompartment area and canopy closure, and the product of subcompartment area and its NDVI, was analyzed.The results showed that they all had good correlativity. Among them, the product of subcompartment area and average of NDVI had the best. The NDVI value of subcompartment pixel could be selected as the auxiliary factor of sampling probability proportional to size (PPS). This method could be used as data smoothing treatment in sampling of subcompartment to raise estimation accuracy．