Abstract: Under the condition of soil culture, three moisture rates and two nitrogen application rates were designed to investigate the effects of water and nitrogen coupling on morphological characteristics and activity of root system in Shanyou 63. The results show that the dry weight, volume and depth of root system increase with higher nitrogen supplying level under less water supplying condition. The vertical distribution of root dry weight could be expressed by logarithmic function, power function, exponential function and polynomial function and each correlation coefficient was more than 0.9. However exponential function was the best. With higher nitrogen supplying level and less water supplying level, the root effective area and α-NA-oxidizing ability increased and the growth of root system accelerated. But root activities were bated with overmuch less water supplying level.