Abstract: Baced on the practical conditions of logging operations in China, the sampled data for Chinese human body and the principle of ergonomics, the international standard "ISO-8334-1985 Forestry Machinery-ortable Chain-saws-etermination of Balance" has been proven to be suited to China’s conditions. It can, therefore be equivalently applied in China. In addition, the paper has probed into the method of balance determination for the portable chain-saws with high handle, which has not been standardized in "ISO-8334-1985" and this paper puts foward that the angle requirement for the longitudinal balance of the portable chain-saws with high handle should not exceed 7?