In this study, a field experiment was conducted in a tea garden with three different biochars derived from rice straw, corn straw, and bamboo. Soil basic physicochemical properties, available nutrient contents, and nutrient accumulation and quality of tea leaves were determined and compared. The results showed that compared with the control treatment (no biochar), the application of rice straw, corn straw, and bamboo biochars increased soil pH by 1.12, 1.02, and 0.77 units, respectively. Biochar treatments significantly reduced the exchangeable hydrogen and aluminum while significantly increasing concentrations such as organic matter, available nitrogen, potassium and phosphorus, exchangeable calcium and magnesium, and cation exchange capacity. Rice and corn straw biochars had no significant influence on mineral nutrient accumulation in tea leaves, however, bamboo biochar enhanced the uptake of magnesium in the tea leaves while reducing the uptake of calcium, manganese, iron, and other nutrients in tea leaves. Biochar treatments had no significant influence on tea yield and contents of tea polyphenols, caffeine, free amino acids, and water extract in tea leaves. In conclusion, compared with corn straw and bamboo biochars, rice straw biochar is more effective in increasing soil pH, decreasing exchangeable H⁺ and Al³⁺, and enhancing soil available mineral nutrients in acidic tea gardens.