Canopy rainfall interception is an important component of water balance in forest ecosystems and plays an important role in the water cycle and water resources management. Studying on rainfall interception across different aged stands of the specific fast-growing merchandise wood species-Chinese fir (Cunninghamia lanceolata), can help us to better understand on water cycling and water resource conservation. In this study, canopy interception process was investigated using the small watershed comprehensive experimental technology at the third watershed (No.Ⅲ) in Huitong National Key Forest Ecosystem Research Station, Hunan. Forest rainfall, throughfall, and stemflow were monitored and the rate of rainfall interception was estimated in young, mid-age, and early-mature stands of Chinese fir plantations from 1983 to 2007. The mathematic Fan model was used to estimate the rainfall interception process. The results showed that (1) the average rainfall interception rates were 26.0% in young stands, 27.9% in mid-age stands, and 29.5% in early-mature stands; the seasonal variation of interception rates was similar in the three stages of Chinese fir plantations, but the interception rates were significantly higher in early-mature stands than young stands, especially within the months when rainfall amount was small. (2) When a rainfall event was amounted to less than 1.0 mm, there was no significant difference in rainfall interception rates for all three stands, which were all over 86%; when the amount of a rainfall event was 1.0-2.0 mm, interception rates considerably declined in the three growth stands. The interception rate was 48.1% in the young stands, 48.7% in the mid-age stands, and 47.1% in the early-mature stands and no significant differences were found in terms of interception rates among the three stands; when a rainfall event reached 2.0-4.0 mm, the interception rates significantly differed in the three stands, with the values of 30.5% in the young stand, 38.4% in the mid-age stand, and 44.1% in the early-mature stand; when a rainfall amount was greater than 100 mm, the interception rates were not significantly different between the three stands with less than 10% of interception rates. (3) The Fan model was suitable for interpreting rainfall interception of Chinese fir plantations in these studied regions.