The invention provides a sexual propagation method of bletilla striata. The sexual propagation method of bletilla striata particularly comprises the steps of processing of capsules, preparation of nutrients, inoculation and cultivation, and bottle out domestication, and is characterized in that in the step of processing of capsules, an alcohol lamp drying mode replaces a filter paper sucking dry mode in the prior art; in the step of preparation of nutrients, combination of banana slurry and humus is adopted; in the step of inoculation and cultivation, only inoculation, germination cultivation and strong seedling cultivation steps are included, the conventional enlargement cultivation process in an existing tissue culturing technology is omitted, and the process is simplified and the cost is lowered while the purposes are achieved; in the step of bottle out domestication, cultivation is performed through humus in a greenhouse, domestication is finished under the condition of controlling the relative humidity, temperature and shading rate, and qualified bletilla striata seedlings are obtained. Bletilla striata seeds are used for scale seedling culturing, the survival rate is high, manual scale propagation of bletilla striata is achieved, and the obtained bletilla striata seedlings are low in contamination rate, high in differentiation rate and stable in inheritable character.