Under the background of global warming, the frequency of extreme climatic heat wave events continues to increase in subtropical region. The high frequency heat wave events severely reduced plants photosynthetic properties, especially when the combined thermal and drought stresses occurred, it will inhibit plant growth, and further lead to plant mortality. However, the response of subtropical tree species photosynthetic characteristics and growth to high-frequency heat waves and their complex stresses is still unclear. In this study, we created a heat wave simulation experiment on subtropical tree species, Phoebe bournei, focusing on the influences of heat waves on the photosynthetic characteristics and growth rates with or without water supplement during heat waves. The results showed that the single heat wave event in wet environment with water supply can resulted in 34% decrease in net photosynthetic rate (Pn) and also decrease in water use efficiency (WUE), but transpiration rate (Tr), stomatal conductance (Gs) and leaf vapor pressure deficit (Leaf_vpd) showed significant increase (P<0.05). This indicates that the Phoebe bournei in sufficient water environment can regulate leaf temperature via accelerating the water evapotranspiration consumption under high temperature stress, which could enhance the resistance of plant photosynthetic characteristics to heat waves. However, there was no significant increase in Tr and Gs in the single heat wave treatment group in drought habitat without water supplement, as well as the different slopes of the linear fit between Tr and Leaf_vpd in dry and wet environments. It suggests that without water supply, heat waves can cause drought stress, reduce the efficiency of leaf cooling, and exacerbate the effect of heat wave on photosynthetic characteristics of Phoebe bournei. The combined drought and high temperature stress also prolonged the recovery process of Phoebe bournei photosynthetic characteristics after heat wave, while Pn recovered to the undisturbed level at 15 days later after heat wave influences, but failed to recover in the combined stress group. In addition, there was a cumulative effect when successive heat wave occurred, which showed a reduction of Phoebe bournei resistance to heat waves, evidenced by the significant variation (P<0.05) of Tr, Gs and WUE during multiple successive heat wave events. But the multiple successive heat wave events did not significantly influence the recovery process of photosynthetic characteristics after heat wave, even caused an increasing of plant height. Under the wet environment with water supply, the Phoebe bournei seeding height relative growth rate of cumulative effect of continuous heat wave was significantly higher than other treatments, but no significant difference was observed in the relative growth rate of ground diameter. Our results indicate that the subtropical tree species, Phoebe bournei, has a strong heat wave resistance in wet environment, but such resistance will largely reduce in dry environment, and the successive heat wave events may also increase the probability of seedling mortality in dry environment. Therefore, studies of plant response to climate change should pay more attention on compound environment stresses or changes in extreme climate patterns.