Abstract: The size structure, survival curve, dispersion coefficient, index of nearest neighbor and Ripley's K function were used to analyze the population structure and distribution pattern of dominant tree species in the ancient tea tree community in Ailao Mountains of Yunnan Province. The results showed that there were 2 894 free-standing individuals with DBH≥1.0 cm recorded in the 1.2 hm2 plot, belonging to 48 species, 38 genera and 22 families. Camellia sinensis var. assamica was ranked the first in terms of importance value with the highest abundance and Lithocarpus xylocarpus was ranked the second, although it had the largest relative dominancy. Then the community should be defined as mid-montane humid evergreen broad-leaved forest with Camellia sinensis var. assamica, L. xylocarpus, etc. being the dominant tree species. Now it is in the climax of succession series. Among 10 dominant tree species, L. xylocarpus, Manglietia insignis, Castanopsis wattii were of declining populations since their seedlings and saplings were scarce and the big trees were numerous. These three species tended to be in random distribution at most of scales, but clump intensity increased as population grew. Camellia sinensis var. assamica, Lithocarpus hancei and Myrsine semiserrata were of stable populations since theirs saplings, middle-sized trees were numerous and the big trees were scarce. Litsea honghoensis, Actinodaphne forrestii, Neolitsea polycarpa and Camellia pitardii were of growing populations since their seedlings and saplings were numerous and the big trees were scarce. These seven species tended to be in clumped distribution at most of scales, but clump intensity decreased as population grew. The spatiotemporal variations of population structure and distribution pattern reflected the competition between these species and the trends of succession of community.