184 plots from larch (Larix Mill.) forests across China were sampled to characterize the height-diameter relationships and investigate the effects of structure and climate on them based on the power function H = aD^b. The results showed that the height-diameter relationship differed greatly among species: b-value of Larix gmelinii (0.65±0.11) and L. olgensis (0.68±0.10) were significantly higher than L. mastersiana (0.51±0.17) and L. potaninii (0.54±0.15) (F=2.34, P=0.026). These differences were significantly influenced by mean annual temperature, but no statistic relationships were detected between stem density, total basal area and mean annual prepetition against b-value. These results indicated that as mean annual temperature increased, a higher proportion of biomass was allocated into diameter growth than height growth (R²=0.09, P<0.001).