Abstract:The effects of temperature on seed germination, seedling morphological and physiologicalbiochemical indexes were studied by different constant temperatures (15 ℃,25 ℃,35 ℃) and variable temperatures (25 ℃/15 ℃, 30 ℃/20 ℃, high and low temperature for 12 h respectively) controlled experiments in laboratory. This paper also discussed the influencing mechanism of temperature on seed germination and seedling growth of Rhododendron agastum. The results showed that: (1) the condition of variable temperature 25 ℃/15 ℃, the seed germination rate (87.69%) and exponential value (8.65) was the highest. (2) The variable temperature 25 ℃/15 ℃ is beneficial for ground diameter, seedling height, average root length and twig increase, and biomass accumulation of roots, stems and leaves of R. agastum. (3) After the seedling leaves was treated at variable temperatures 25 ℃/15 ℃, the total leaf chlorophyll, soluble sugar and soluble protein contents were the highest, while the MDA content, CAT activity and SOD activity was lower. The research showed thatthe optimum temperature for seed germination and seedling growth of R. agastum was 25 ℃/15 ℃(day/night). The growth was significantly inhibited at high temperature (35 ℃) and low temperature (15 ℃).