Abstract: The effect of high temperature stress on cell membrane permeability (electrolyte leakages and Pi leakages) and photosynthetic pigment in leaf discs of peach andpomelo and their relations to heat-resistance were studied.The results showed that: ①High temperature stress induced an increase in the leakage of electrolyte and Pi of theleaf discs dipped in distilled water for 24 h,exposed to light or dark at room temperature, and lightness was advantage to membrane repair.②High temperature stress induced a decrease in Chl content and an increase in Chl a/b ratio in leaf discs of peach andpomelo.③The physiological responses above mentioned correlated well with speciesheat-resistance and may be used as screening indexes.