Abstract: Long-term consumption of high-fluoride tea probably causes drinking tea fluorosis. This article ascertained the regulation mechanism of available fluoride content in tea garden soil, to provide theory of controlling soil fluoride pollution and reducing fluoride content of tea leaves. Laboratory incubation tests were conducted, using 0-20 cm and 20-40 cm layers soils from two tea gardens of Hunan Province as experiment materials, to study the influence of different forms and addition amount of calcium ion on soil pH and available fluoride content. The results showed that soil pH value fell to 3.5 from 4.0-3.7 and soil water soluble fluoride content increased obviously when the addition amount of Ca(NO₃)₂ and CaCl₂ was increased. With the increase of addition amount of Ca(OH)₂, the soil pH value change ranged from 4.0 to 5.2, soil water soluble fluorine content was decreased obviously at first, then increased. Soil exchangeable fluoride content was decreased when applied all the three forms of calcium ion into soil. In this experiment the range of soil pH was 3.5-6.0, water soluble fluoride content was increased when the soil pH was below or above 5.0, especially when soil pH was below 4.0. Therefore, applying proper amount of dolomite powder, Ca(OH)₂ to acidified soil or applying CaCl₂, Ca(NO₃)₂ and aluminum salt to alkaline soil to adjust soil pH to about 5.0, can effectively reduce the available fluorine content in tea garden soil.