Ten typical rice varieties were selected to study the relationships between the characteristics of root system and aboveground parts through field experiments and field root bag methods. The results showed that root mass had positive correlation with aboveground mass and total mass at different growth stages. The oxidizing activities of root had significant correlation with aboveground performance at tillering stage and rice yield at ripening stage. However, root/shoot ratio had negative significant correlation with yield at heading and ripening stage, the correlation coefficients were (-0.861 6) and (-0.889 0) respectively. In order to obtain maximize yield, the results implied that reduction of root system to a reasonable size may be an effective way to improve the yield of crop.