The genus Bletilla, composting about six species, is endemic to Asia with a distribution pattern from N Myanmar and Indochina through China to Japan. The usage of the plants of Bletilla, mainly Bletilla striata (Thunb.) Reichb. f., includes art (Chinese painting and writing), the production of porcelain, and medicine, as well as vegetable dyes for dyeing cloth in some minority people in Guizhou and Yunnan Province, China. Those species are also commonly used as a horticultural subject covering both indoors and out cultivation in North American and European areas. As the traditional herb medicine using more than 1500 years, pseudobulbs of Bletilla have been widely used in Eastern Asian countries to treat alimentary canal mucosal damage, ulcer, bleeding, bruises and burns. The pseudobulbs also show antibacterial, anti-inflammatory, antiphlogistic and demulcent properties, and thus use in treating pneumonophthisis, pneumonorrhagia, tuberculosis and haemorrhage of the stomach or lung. Moreover, it is suggested that cationic polysaccharide from Bletilla strata can serve as a non-viral nucleotide drug delivery vehicle for oligonucleoide or siRNA targeting to immunology system. Apparently, there is a huge potential demand for the pseudobulbs of Bletilla in future. At present, the cultivation of Bletilla is only limited to the temperature areas of North America and Europe for the horticultural purpose, and the using of pseudobulbs of Bletilla for other purpose especially for medicinal purpose is basically based on wild resources. Undoubtedly, the wild resource of Bletilla will rapidly decrease in Eastern Asian Countries due to over collections as well as habitat destruction and fragmentation. The conflict between the great market demand for the pseudobulbs of Bletilla and the decreased wild resource has necessitated the breeding of cultivars for high yields, high concentrations of active components, and high resistance to diseases. Unfortunately, no cultivar has been bred so far and selections of superior individuals meeting the requirements are now underway from field and hybrid progenies. So we strengthened research on ecophysiological characteristics growing development of Bletilla. By using a Li-6400XT portable photosynthesis system, this paper studied the ecophysiological characteristics of photosynthesis-transpiration coupling of Bletilla striata during daily variation. The results showed that: (1) The diurnal change in photosynthetic active radiation (PAR) and leaf temperature (Tl) are similar to each other, peaking around midday; (2) Stomatal conductance (Gs), net photosynthetic rate (Pn) and transpiration rate (Tr) presented a bimodal pattern; (3) Pn shows significant positive linear correlation with Tr (the slopes are 2.38 and 3.78, with correlation coefficients of 0.883^{* *} and 0.954^{* *} for sunny and cloudy days, respectively) and presented a good linear coupling with photosynthesis-transpiration of Bletilla striata during daily variation; (4) The regression lines of PAR-Pn and PAR-Tr, Tl-Pn and Tl-Tr, and Gs-Pn and Gs-Tr are similar to each other,while no significant correlation was observed between Pn and Tl; (5) Both Pn and Tr showed a positive dependence on PAR, Tl and Gs, with Gs being the main factor affecting Pn and Tr. Bletilla striata is a type of shade perennial plant able to flourish in conditions of low light intensity. The response of the physiological and biochemical indexes in Bletilla striata seedling leaves was compared under simulated drought stress using different concentrations (0, 5, 20, 40, 60g/L) of PEG 6000 solution. The result showed that chlorophyll content takes on a negative correlation (R²=0.7854) with the increasing PEG concentration, and relative conductivity takes on a positive correlation (R²=0.8755) with the increasing PEG concentration. Under osmotic stress, using different concentrations of PEG 6000 solution, the relative water content of Bletilla striata showed a lower rate of reduction.