In this longterm experiment,seven treatments were conducted to investigate effects of the green manure combined with chemical fertilizer on soil nutrients,soil water retention and supply capacities.The results showed that when the green manure was applied,chemical N was not required to apply,but chemical K and P should be applied.The rice yields did not change significantly as chemical fertilizer reduced.Water retention and supply capacity among treatments showed the same trend of green manure plus 40% chemical fertilizer > green manure plus 60% chemical fertilizer > green manure plus 80% or 100% chemical fertilizer > chemical fertilizer alone or green manure alone > the control.Compared with.5%～30.5%,respectively,indicating that chemical fertilizer combined with green manure enhanced the water retention and supply capacities and less water was better,while either of them applied alone showed limited effects.Therefore,when green manure (22 500 kg/hm2) was applied,chemical fertilizer application could be reduced by 60% and even more.