Lianas are an important growth form in tropical forests around the world; however they are relatively unknown in southeast Asia. We identified measured and determined the climbing and disperal modes for all lianas ≥ 0.2 cm in diameter in five 0.1 ha (20 x 50 m) plots in three common forest types at the tropical-temperate transitional zone in Xishuangbanna SW China: montane forest evergreen broad-leaved forest and seasonally wet forest. The mean density of lianas varied significantly among the three forests with 445 276 and 301 individuals per plot in the seasonally wet montane and evergreen forests respectively. In all three forests combined we found a total of 147 liana species representing 48 families and 75 genera; however similarity coefficients between the forests were low. Mean species richness was 40 26 and 21 species per plot in the seasonally wet montane and evergreen forest respectively. Fisher’s α differed significantly among the three forest types with seasonally wet forest having the highest and evergreen forest the lowest values. In all three forests most lianas were stem twiners and scramblers with relatively few hook tendril and root climbers. Liana species were mostly wind dispersed in the evergreen forest but animal and gravity dispersed in the other two forests. Compared to other tropical Asian tropical forests the diveristy and abundance of lianas is relativley high in Xishuangbanna which may be due to the relatively warm climate as well as high seasonal rainfall and high rates of disturbance and forest fragmentation.