The invention discloses a special slow-release fertilizer taking biomass granular carbon as a matrix for tea trees and a preparation method thereof. Granular carbon prepared from agricultural abandoned biomass such as corncobs, peanut shells, rice husks and edible mushroom matrixes, taken as a matrix material, is compounded with nitrogen, phosphorus, potassium and other nutrient elements essential to the growth and development of the tea trees by utilizing the microporous character and strong adsorption capacity of the granular carbon, so that the special slow-release fertilizer taking the biomass granular carbon as the matrix for the tea trees is prepared. According to the invention, the biomass granular carbon is black biomass granular carbon particles formed after incomplete combustion of the agricultural abandoned biomass under a hypoxic condition, has various properties similar to those of soil humus, is very strong in capacity of adsorbing and maintaining nutrients and moisture, and furthermore, and has an effect of stimulating the growth of crops and a good slow-release performance for the nitrogen, phosphorus and potassium; the slow-release fertilizer prepared in such a way can effectively meet the requirements of the tea trees for nutrients in the whole growth period after being applied once; and in addition, the special slow-release fertilizer has the characteristics of enhancing the soil fertility, improving the soil structure, being efficient and environmentally-friendly, and the like, thereby being beneficial to large-scale popularization and application in tea tree production.