Abstract: A solar greenhouse experiment was carried out to search the optimum mode of water- saving irrigation for cucumber（Cucumis sativus L.‘Jinyu 5’）. Different irrigation levels（150，300 and 450 m³ · hm^-2 each time）were set. Cucumber plants were either own-rooted or grafted onto the rootstock（Cucurbita ficifolia）. Then root distribution，commodity yield and water use efficiency（WUE）were investigated. The results showed that in most cases，a modest reduction in irrigation quantity didn’t significantly affect the growth，the vertical distribution and absorption of cucumber’s root. Compared with conventional irrigation（450 m³ · hm^-2 each time），irrigation of 150 m³ · hm^-2 each time didn’t significantly affect the yield of own-rooted and grafted cucumber，thus significantly increased WUE. In irrigation of 150 m³· hm^-2 each time，the roots of grafted cucumber were strong and stout，a large number of capillary roots were induced and distributed to the deep soil，so that the yield of grafted cucumber was higher significantly than that of own-rooted cucumber. On the whole，in the reduction of irrigation，grafting may obtain favorable effects of root-promoting，water-saving and high yield.

Key words: cucumber, irrigation, graft, root distribution, yield, water use efficiency