Abstract: 【Objective】 Guizhou small-leaved Kuding tea(Ligustrum robustum)originates from the fresh leaves of Ligustrum robustum(Rxob.)Blume, which has been one of the major substitute tea drinks in our country. At present, the development of Guizhou small-leaved Kuding tea as a health beverage has been very extensive. Therefore, Guizhou small-leaved Kuding tea is recognized as being of high economical value and developmental prospect. Soil moisture is the main source of plant physiological and ecological water supply. Soil moisture content and change have a direct impact on plant growth, development and yield. Therefore, the appropriate range of soil moisture is of great significance to the improvement of yield and quality of Guizhou small-leaved Kuding tea. The purpose of this research was to determine yield and quality corresponding to different soil moisture levels and the soil moisture range that is optimal for the yield and growth of Guizhou small-leaved Kuding tea. 【Method】 Three-year-old L. robustum seedlings were grown as experimental material using the potted water control method. The experimental seedlings were subjected to six water gradients for an experimental period of 90 days. At the end of treatment, the light green leaf buds of L. robustum were selected for quality indicator determination(i.e., soluble sugar, flavonoids, tea polyphenols, free amino acids, water extracts and tea saponin). The bud leaf was selected for yield indicator determination(i.e., leaf area, length and width). Leaf area per plant was determined with the scanning method. Yield indicators measurements followed the method of graded picking to explore the effects of different soil moisture content on leaf morphology and the main chemical components of Guizhou small-leaved Kuding tea. 【Result】① Leaf indexes(i.e., leaf number, single leaf area, leaf length and leaf width)and tea production indexes(i.e., germination number per plant, bud weight, weight of 1 leaf with 2 buds, and weight of 1 leaf with 4 buds)were the highest when the relative soil moisture content was 85%, whereas no significant differences were observed among indexes in the 70%-100% soil moisture content treatment range. Mortality rates increased with decreasing moisture content. Concentrations of soluble sugars, water extract, tea polyphenols, free amino acids, total flavonoids and tea saponin all increased at first and then decreased with decreasing relative soil moisture content. Concentrations of soluble sugars, tea polyphenols, free amino acids, total flavonoids, and tea saponin all decreased when the relative moisture content of the soil was less than 55%. 【Conclusion】 When the relative water content of the soil remained stable in the range of 70%-85%, the contents of amino acids, tea polyphenols, soluble sugars, flavonoids, and tea saponin, which reflect the quality of Guizhou small-leaved Kuding tea, increased significantly, and the yield and germination ability followed the same trend. However, the plants of Guizhou small-leaved Kuding tea suffered water stress(when relative water content of soil was low)at 40%, and the physiological functions of leaves were seriously inhibited. This led to a decrease in the quality and yield of Guizhou small-leaved Kuding tea, which was not conducive to its growth. The above shows that in the production practice, it is of great significance to keep the soil moisture in a suitable range through rational irrigation and water supply to obtain high yield and quality of Guizhou small-leaved Kuding tea. Therefore, to obtain the best yield and quality, and considering effective use of water, 70%-85% relative soil water content, i.e., 28.4%-34.5% soil water content should be used as the water supply range for cultivation of Guizhou small-leaved Kuding tea.