Abstract: Taking Rhododendron latoucheae,R.rivulare and R.molle as experimental materials, and an artificial climate incubator to simulate high temperature stress was used, the effects of different high temperature stress（14 hours day/10 hours night, control 25 ℃/21 ℃,mild stress 32 ℃/25 ℃,moderate stress 38 ℃/28 ℃,severe stress 42 ℃/31 ℃） on plant height, ground diameter, leaf relative water content, biomass, root shoot ratio, chlorophyll content, SOD activity, malondialdehyde content, soluble protein content and soluble sugar content of three species of Rhododendron were studied, in order to identify Rhododendron varieties with stronger heat resistance.The results showed that with the degree of high temperature stress increased, the plant height increment, ground diameter increment, leaf relative water content, and total biomass in the growth indicators of the three Rhododendrons showed a significant decrease, and the root shoot ratio showed a trend of first increasing and then decreasing;SOD activity of the leaves of the three Rhododendrons showed a trend of gradual increase or first increase and then decrease,MDA content of the leaves of the three Rhododendrons showed a trend of gradual increase,chlorophyll a and chlorophyll b content of the leaves of the three Rhododendrons showed a trend of gradual decrease,soluble protein and soluble sugar content of the three Rhododendrons showed a trend of gradual increase or first increase and then decrease,compared with the control,there was an increasing trend overall.