Abstract: The experiment was studied to improve water use efficiency of cucumber in greenhouse and explore cultural model with economizing water. As the contrast of irrigation amount in experience of farmer, the cucumber were tested as the experimental materials to study the effect of controlling irrigation quantity on photosynthetic physiology, yield and water use efficiency of grafted cucumber and self-rooted cucumber in the greenhouse. The results showed that as follows： there were obvious effects of appropriately reducing irrigation quantity to promote photosynthesis and improve water use efficiency. The treatment of I1 was significantly more than the treatment of I2 in photosynthesis and chlorophyll content of cucumber. Compared with self-rooted cucumber, grafted cucumber had better performance in photosynthesis, yield, and water use efficiency. In the treatment of II,yield and water use efficiency of grafted cucumber respectively improved 7.16%,compared with self-rooted cucumber; In the treatment of I2,yield and water use efficiency of grafted cucumber respectively improved 7.83%,compared with self-rooted cucumber. On the whole, in this experiment, the treatment of I1-G had best performance in the hand of photosynthesis, yield, and water use efficiency, was a better cultivating and irrigation mode, and had a promotional value.