In the process of transplanting and acclimating tissue culture seedlings of Bletilla striata in summer，they will face fluctuating light and heat stress at the same time.The tissue culture seedlings of Bletilla striata in June 2021 transplanting greenhouse were used to determine the variation trend of the acclimation time on the growth and physiological indexes of Bletilla striata transplanting seedlings to study the effect of light-temperature coupling in summer on the growth and development changes of acclimated seedlings of Bletilla striata and provide a scientific basis for the adaptive exercise of Bletilla striata in summer.At 90 days of acclimation，the temperature （25 ℃，30 ℃，35 ℃ and 38 ℃） and fluctuating light （50 mmol/（m²·s），2 min； 1 000 mmol /（m²·s），2 min） were set to simulate the light and temperature stress of Bletilla striata in summer.The results showed that the root-shoot ratio of Bletilla striata seedlings increased first and then decreased within 90 days.The content of polysaccharide in the tuber increased by 51% in 90 days compared with that in 60 days.Under the combined stress of fluctuating light and high temperature，the amount of carbon assimilated by Bletilla striata was lost 2-3 times.The F_v/F_m，F_PSII，qP，F_v'/F_m' and ETR of transplanted Bletilla striata seedlings were reduced，and F_NPQ and NPQ were increased with the increase of temperature.It is indicated that the high temperature and fluctuating light in summer cause serious harm to the growth and development of Bletilla striata，which is not conducive to the transplantation and domestication of Bletilla striata.