Xingyuangtong handhold forest inventory instrument is a microcomputer_based Hi_tech product integrating remote sensing、mobile GIS and GPS, which is developed by 3S research center of Shenzhen Polytechnic. It can be used in forest resource inventory, area calculation on map, area survey on the spot, compartment and sub_compartment mapping and editing based on remote sensing images or scanned relief maps, interactive query and amendment between graphics and its attributes, etc. On the basis of theory analysis of area survey principle, the practical area survey precision of nine different_sized plots in different period of time and under different interfered conditions is analyzed in order to study the possible precision of area survey on the spot by using this product. It is demonstrated that Xinyuantong handhold forest resource inventory instrument can meet the precision needs of returning the grain plots to forestry, acceptance check of forestation land, area survey of compartment and sub_compartment, etc. This product can be widely used in forest resource inventory.