Abstract: This indoor incubation study aimed to evaluate the ameliorating effects of four biomass materials, including rice straw, wheat straw, biochar and sheep manure, on acidic soil at a tea plantation. The results showed that the pH of the soil incorporated with rice straw, wheat straw, biochar, and sheep manure increased by 0.72, 0.53, 0.77, and 0.72 units, respectively, at 2% addition level, and 0.89, 0.76, 1.16, and 1.32 units, respectively, at 4% addition level over control. In addition, the applications significantly decreased the contents of exchangeable acidity and exchangeable aluminum, while increased the exchangeable and saturation on cations in the soil. The amelioration of the soil was enhanced with increasing biomass addition. Different from the other materials, sheep manure significantly increased the cation exchange capacity (CEC) and nitrate nitrogen (NO₃ -N) content in soil, biochar exerted no significant effect on NO₃ -N, and rice or wheat straws significantly decreased NO₃ -N. Consequently, sheep manure followed by biochar were considered the choice materials for acid alleviation on tea plantation soil.