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Bletilla striata is a perennial herb belonging to the family Orchidaceae, has been used as Chinese folk medicine. Seed quality is key to get large number of B. striata seedlings, and the seed setting rate is a very important standard to evaluate the fruit quality. It is a quick method to rough evaluate seed setting rate through the fruit form. In this study, the correlation between fruit form(fruit weight, length and diameter)and seed setting rates among 26 infructescences (87 fruits) of B. striata were analysed, the seed embryo sizes of ten different sizes of B. striata fruits were measured, and the weights of 400 seeds were calculated and the weights of single seed were obtained. The results showed that correlation between fruit weight and seed setting rate were the most close, the coefficient of correlation was 0.786, reaching to moderate degree; the second close was fruit diameter, the coefficient of correlation was 0.634; and the last was fruit length, the coefficient of correlation was 0.553; the average setting rate of 87 fruits was 50.43%. The correlation between fruit form and seed embryo size was at a low degree, developmental state of seed embryo could not be known through the fruit form; the average diameter of embryo was 177.9 μm, the biggest was 241.9 μm, the smallest was just 64.5 μm; and the average length of embryo was 359.0 μm, the biggest was 528.6 μm, the smallest was just 114.3 μm, the results showed that the mature seed embryo size of B. striata mainly focus on 150-200 μm in diameter, the ratio was 62.34% in this range, and 300-400 μm in length, the ratio was 68% in this range. The average weight of single seed was 3.90 μg, the seeds in the biggest fruit of the 87 was 39 488, and the average number was 10 436, according to calculation, the average number of have embryo seeds in a single fruit was 5 263, it could gain a large number of B. striata seedlings through the sterile culture. In conclusion, fruit weight and full degrees (diameter) can be used to evaluate fruit quality (seed setting rate) of B. striata. [ABSTRACT FROM AUTHOR]