In order to study the water conservation function and its change tendencies of Taiwania flousiana plantations, T. flousiana plantations at different ages (9, 17, 25 and 37 years old) in Nandan county of Guangxi were taken as research objects, and the water holding capacities of the canopy, undergrowth vegetation lager, litter lager and soil lager of the T. flousiana plantations were studied by the indoor soaking method and the cutting ring method. The results showed that:(1) The water holding capacity of the canopy and the vegetation layer under canopy for the different ages of T. flousiana plantations ranked 18.79~28.37 and 1.27~4.72 t/hm², respectively. The water holding capacity of the understory vegetation increased significantly with the increasing of forest age (P < 0.05). The litter amount was 2.23~10.67 t/hm², and the maximum water holding capacity was 5.95~34.15 t/hm², which increased significantly with the increasing of forest age (P < 0.05). (2) Soil non-capillary porosity and total porosity of different T. flousiana plantations were 5.60%~15.68% and 48.27%~66.85%, respectively. Soil non-capillary porosity and total porosity in 0-20 and 20-40 cm soil layers were significantly higher than those in 40-80 cm soil layers (P < 0.05), and increased with the increasing of forest age. The maximum water holding capacity and the effective water holding capacity of the soil layer (0-80 cm) were 4 196.74~4 416.47 and 540.13~648.07 t/hm², respectively. The maximum water holding capacity and the effective water holding capacity of the 0-20 and 20-40 cm soil layers increased with the increasing of forest age. (3) The total water storage capacity of 9, 17, 25 and 37 years old T. flousiana plantations were 4 222.43, 4 272.55, 4 355.29 and 4 484.32 t/hm², respectively, which increased with the increasing of forest age. In conclusion, the T. flousiana plantations could improve the soil structure and moisture condition and enhance the water conservation performance of stands.