Abstract: The root system of a 6-year mixed stand of Chinese fir and Homana is studied by" soil column" and " standard sample tree" methods. The fine root(less than 2 mm in diameter) biomass of individual tree of Chinese fir in mixed stand is 14.5%higher than in pure stand, with even distribution and extending to subsoil, and those of Chinese fir and Homana in mixed stand are distributed in different soil layers,which is favorable for improving soil structure and providing more nutrients for the growth for Chinese fir.