Abstract: Filed experimental investigations on the influence of RDI ( Regulated Deficit Irrigation ) were conducted in a 17 year-old peach orchard at Beijing Institute for Horticultural Research from 1988 to 1990. Irrigation treatments were so designed that 80%, 40% and 20% of evaporation from U.S. Class A Pan could be replenished during the period of RDI. Measured leaf water potentials of different treatments showed that stressed trees had more negtive leaf water potentials during the period of RDI and less negtive potentials after ending RDI, i.e. restarting full irrigation than the control, which were fully Irrigated at all times. Shoot growth of 40% and 20% treatment trees was significantly depressed as compared with that of 80% treatment ( control ) trees. Growth of fruits on 40% and 20% treatment trees was slightly slower during RDI peroid and significant faster after restarting full irrigation than that on 80% treatment. As results, yields of fruit on both 40% and 20% treatments trees were of 20% higher than those on 80% treatment trees with 95% significancy together with a substantial saving in irrigation water.