Dahurian Larch (Larix gmelinii) is a dominant tree species in Eurasian boreal forests, and has a broad biogeographical range under divergent habitats. This makes this tree species ideal for investigating tree adaptation to environmental change. Leaf carbon use efficiency (CUE_L) is closely associated with tree carbon metabolism, and tree growth and development. Furthermore, CUE_L is sensitive to environmental change. In this study, we measured the CUE_L of 30-year-old Dahurian larch trees from six provenances in a common garden at the Maoershan Forest Ecosystem Research Station (45°20'N, 127°30'E) in Northeast China for three years (2009-2011). The six provenances were located across the natural distribution range of the larch, spanning approximately 4° in latitude (48-52°N), 5℃ in mean annual temperature (-2.3-2.6℃), and 200mm in mean annual precipitation (425-622mm). The differences in aridity index (ΔAI, AI = mean annual evaporation/ mean annual precipitation) between the current sites and original locations of the seed sources were used as indices for environmental change gradients (i.e., six provenances were represented as six gradients of environmental change). Our goal was to explore the impacts of environmental changes on larch CUE_L and the factors influencing the impacts. We found that CUE_L decreased significantly with increasing ΔAI (P < 0.05). The CUE_L was correlated positively with leaf nitrogen concentration, leaf phosphorus concentration, leaf mass per area, and leaf chlorophyll concentration, but the trees with higher ΔAI values had greater slopes of these relationships. Furthermore, the CUE_L was correlated positively with the mean annual precipitation of the seed source original locations (P=0.05), but negatively with the AI of these locations (P < 0.01). The CUE_L also tended to increase with increasing mean annual temperature and mean annual evaporation of the seed source original locations, but these relationships were not significant (P > 0.05). Our results suggest that environmental changes drive the adaptive variability in CUE_L of the larch, which is probably attributed to its genotypic adaptation to the environment of the seed source locations.