【Aim】To provide theoretical basis for the heat-tolerance identification of genus Camellia, the discovery of heat-tolerance germplasm and the breeding of new cultivars.【Method】In this study, C. uraku and ‘Wirlinga Cascade’, a foreign cultivar were used as reference materials,7 new cultivars of cluster-flowering camellia were selected as test materials,after short-term (5h) and long-term (7d) high-temperature treatment, morphological, physiological and photosynthetic characteristics were observed. The heat tolerance was evaluated by correlation analysis and principal component analysis.【Results】(1) The contents of chlorophyll and carotenoid, chlorophyll a/b, Pn and Gs all increased, Fv/Fm, Fv/Fo and ETR remained at a high level, and also ‘Chuizhi Fenyu’ and ‘Wirlinga Cascade’ did not appear heat damage at 7 days of high temperature stress.Pn and Gs of 'Jinye Fenyu', 'Shangzhi Huazhang' and 'Meigui Chun' all decreased significantly under high temperature stress, while Ci increased. Among them, the Fv/Fm, Fv/Fo and ETR of 'Jinye Fenyu' and 'Shangzhi Huazhang' were significantly reduced, and after 7 days of long-term high temperature stress, these 3 cultivars showed serious heat damage or death. (2)15 individual indicators were converted into 4 independent comprehensive indicators with cumulative contribution rate of 90% through principal component analysis.The comprehensive weight values of chlorophyll content, carotenoid content and lutein content were higher at 5h under high temperature stress, and the comprehensive weight values of chlorophyll a/b, Fv/Fm, qP and qN were higher at 7d under high temperature stress. Under high temperature stress for 7 days, from the largest to the smallest of comprehensive evaluation value D was as follows: Camellia uraku >‘Wirlinga Cascade’>‘Chuizhi Fenyu’>‘Shangzhi Yueguangqu’>‘Shangzhi Huanlesong’> ‘Sweet Gem’>‘Meigui Chun’> 'Shangzhi Huazhang' >‘Jinye Fenyu’.【Conclusions】According to the comprehensive evaluation value D, the 9 cultivars were divided into 3 heat tolerance grades, 'Chuizhi Fenyu' and ‘Wirlinga Cascade’, were heat tolerance cultivars, 'Shangzhi Yueguangqu', 'Shangzhi Huanlesong' and 'Sweet Gem' were medium heat tolerance cultivars, and 'Meigui Chun', 'Shangzhi Huazhang' and 'Jinye Fenyu' had the weakest heat tolerance,the heat resistance of C. uraku needs to be further verified.Chlorophyll content, carotenoid content, xanthophyll content can be used as the key indexes to analyze the short-term high temperature stress of Camellia. Chlorophyll a/b,Fv/Fm,qP, qN,these 4 indexes can be used as the key indexes to analyze the long-term high temperature stress of Camellia.