Soil acidity is an important environmental element for non–polluted tea production. Soil samples, within 20 cm of surfaces in bleached paddy soil, yellow earth and acid purple soil at the same toposequence in Mingshan county of west Sichuan, were collected in spring, summer and autumn, and soil pH, exchangeable acidity, hydrolytic acidity, pH buffer capacity and lime requirement were further measured. The results showed that: ① pH values of 3 types of tea garden soils were lower than 4.5. Among of them, that of yellow earth was the lowest with the mean value 3.79, and the maximum value 4.19. Hence, the soils were not conducive to non–polluted tea production, and must be improved. Among of 3 types of tea garden soils, exchangeable H+ content was the highest in yellow earth, exchangeable Al3+ content and exchangeable acidity (include H+ and Al3+) was the lowest in bleached paddy soil. However, the exchangeable acidity was mainly composed of exchangeable Al3+ for every soil. For hydrolytic acidity, acid purple soil was significantly higher than that of bleached paddy soil, but there was no significant difference in hydrolytic acidity between yellow earth and acid purple soil or bleached paddy soil. The hydrolytic acidity in bleached paddy soil was mainly composed of non–exchangeable acidity, but that of yellow earth and acid purple soil were mainly composed of exchangeable acidity. ② the exchangeable H+ and Al3+, exchangeable acidity and hydrolytic acidity were lower in summer than that in spring or autumn respectively, which were driven by climate and biology factors. ③ the soil pH buffer curves of 3 types of tea garden soils were all presented in “S” shape, but there were differences in soil buffer capacity among the 3 types of tea garden soils. The soil buffer capacity of acid purple soil, yellow earth and bleached paddy soil decreased successively. ④ the lime requirement in acid soil must be determined using calcium chloride exchange– calcium hydroxide titration firstly, and then adjusted by field experiments. Meanwhile, it should not be more than the lime requirement determined by hydrolytic acidity. Among 3 types of tea garden soils, the bleached paddy soil was the lowest in lime requirement if soil pH was adjusted to the same value.