The invention discloses a black tea improving selenium enrichment processing method. The steps are as follows: firstly, one-bud two-leaf dried green tea is employed as a raw material; secondly, dry selenium enrichment yeast powder is taken and prepared into a selenium enrichment yeast aqueous solution for standby, namely, selenium enrichment yeast powder is weighed and dissolved in pure water, and a yeast solution is prepared; thirdly, raw green tea is spread on a water sieve, the selenium enrichment yeast solution is loaded into a watering can and is sprayed in the raw green tea uniformly; fourthly, the tea after spraying is sealed by a plastic bag and is allowed to stand; fifthly, the tea is placed in a manual climatic box and is subjected to piling fermentation, the temperature is 43 DEG C-47 DEG C, the humidity is 82%-87% and the fermentation time is 12-15 days; sixthly, after fermentation is finished, the tea is put in a tea drying machine and dried, the temperature and the time are controlled within certain ranges, and a selenium enrichment black tea finished product is obtained. The technology is simple, operation is convenient, and fragrance is lasting. The finished product meets the national selenium enrichment standard, the tea quality is improved and nutrition and health care values of traditional black tea are raised.