Guizhou is one of the provinces with the most abundant tea variety resources in China. The tea garden area is large, but the economic output value is low. The summer and autumn tea resources are seriously wasted and the variety structure is single. The dark tea Maocha was used as the raw material, and the Fuzhuan Brick tea golden flower fermentation agent was artificially inoculated to optimize the flowering process conditions of loose tea, and the changes of physical and chemical indexes and fungal diversity were studied. The effects of different factors on the flowering of dark tea loose tea were analyzed by monofactorial experiments and orthogonal optimization test. The results showed that the optimum conditions were as follows: moisture content was 30 %, temperature was 28 ℃, fermentation time was 9 d, inoculation amount 1:100 (m/m). Under these condition, the number of Aspergillus cristatum was 3×108 CFU/mL, the water content, total ash content, tea polyphenol content, free amino acid content, water extract content was respectively are 3.0%, 6.8%, 12.0%, 2.4%, 42.6%. After the above optimization, Jinhua lush, plump, soup was yellow and bright, taste of alcohol. High-throughput sequencing technology was used to analyze the fungal diversity at different fermentation time. The results showed that the relative abundance of Aspergillus reached 98.8 % after 3 days of fermentation. This study optimizes the process conditions of Guizhou loose tea, which is of great significance to improve the quality of Fuzhuan brick tea, and provides reference for the study of other loose tea flowering process.