The invention discloses a processing method of agrocybe aegerita mycelium fermented tea and a product of the method. On the premise that no culture auxiliary material is added, tea serves as a culture medium for growth of agrocybe aegerita mycelia, no foreign contaminant exists in the whole process, and the safety of the product is guaranteed. A large number of amino acid substances and polysaccharide substances can be synthesized in the culture process of the agrocybe aegerita mycelia, and the freshness of taste of the product and the richness of substances contained in the product are improved. In addition, in the culture process of the agrocybe aegerita mycelia, ingredients containing in the tea can be subjected to various chemical changes, particularly, natural oxidation of tea polyphenol substances, and the bitterness is reduced. By means of the combined action of the chemical changes of the above-mentioned substances, the quality and value of the tea serving as the culture medium are improved finally, and the tea product with a good commercial prospect is provided for the market.