Abstract: This study aims at improving cucumber heat tolerance through grafting. By hydroponic cultivation, the authors took Cucurbita ficifolia, Cucurbita moschata, Cucurbita maxima × Cucurbita moschata‘Yongzhen No.8’, Luffa cylindrica‘Wuyexiang’and Momordica charantin‘Aomei’as rootstocks, and Cucumis sativus ‘Chunqiuwang‘No.2’as scion, to analyze the change of growth, photosynthesis and biochemical indexes of cucumber seedlings treated by normal temperature (25℃) and high temperature (35℃) in rhizosphere for 5 d and recovered for 5 d. The results showed that grafted cucumber seedlings on different rootstocks had different plant height, stem diameter, blade number and leaf area under high temperature stress in rhizosphere, the increment of grafted seedling of Luffa cylindrica‘Wuyexiang’was the largest, and its leaf net photosynthetic rate (Pn), antioxidant enzyme activity and proline content were significantly higher than other kinds of grafting seedlings, at the same time, its malondialdehyde (MDA) content was the lowest. It is suggested that Luffa cylindrica‘Wuyexiang’taken as rootstock for grafting cucumber could improve the tolerance of rhizosphere high temperature, and provide a theoretical basis for studying cucumber heat resistance.