Abstract: In order to provide theoretical basis for screening better heat-resistant materials of Ginkgo biloba, two-year-old G. biloba seedlings were respectively treated with the temperatures of 40℃, 44℃, 48℃ and 28℃ (control) for 4 h. The morphological characteristics and the physio-biochemical indexes such as relative electrical conductivity, malondialdehyde (MDA) content, superoxide dismutase (SOD) activity, the contents of ascorbic acid (ASA), soluble protein and soluble sugar were determined. The results showed that G. biloba developed a series of changes in physiology and biochemistry after heat stress, although part of indices changed slightly among 28℃, 40℃ and 44℃, but every index ascended sharply from 44℃ to 48℃; morphological characteristics were not influenced when the temperature was below 40℃, but the seedlings withered slightly at 44℃, the results indicated that the changes of physiology and biochemistry were earlier than the changes of morphological characters, the changes of morphological character were the results of physio-biochemical changes; while G. biloba resisting to heat stress, SOD, ASA, soluble sugar and soluble protein played a positive role; there was significant difference about MDA content among under different temperature treatment, as well as the temperature and MDA content had a good linear relationship, so MDA was regarded as the best index for filtering heat-resistant cultivars, whereas for other indexes, they could be used for screening heat-resistant cultivars only with appropriate temperature; there was significant difference for every index between under heat stress of 48℃ and control, when the duration of treatment was 4 h, 48℃ was more appropriate temperature for screening heatresistant cuhivars than other temperature.