1. Alpine plants possess unique traits owing to their adaptation to alpine environments. However, it remains unknown whether leaf trait relationships of alpine plants can be captured by the two general trait dimensions of organ size and resource economics. 2. We hypothesized that, beyond the trait dimensions of leaf size and resource economics, non-structured carbohydrates (NSCs) would reflect an important dimension of cold-tolerance in alpine plants. 3. We measured 12 leaf traits critical to leaf construction, growth, and stress resistance in 225 site species, ranging from 7 sites along the alpine steppes to alpine meadows on the Tibetan Plateau. We also examined the cold-tolerance of 11 species at one of these sites by estimating the lethal temperature causing 50% frost damage (LT₅₀). We investigated the variation and potential leaf trait dimensions of alpine plants and verified whether the third leaf trait dimension is related to cold-tolerance by analyzing the relationships of NSCs and LT₅₀. 4. The majority of variations in 12 leaf traits of alpine plants were captured by three trait axes, in which leaf carbon (LCC) and NSCs (including starch, LSC and soluble sugars, LSS) were clustered in a new dimension (PC3) beyond leaf size and structure, and resource economics. Although LCC, LSC and LSS all showed negative correlations with MAT, a significant negative correlation was only found between LSS and LT₅₀. It indicated that PC3 was able to reflect the cold-tolerance of alpine plants to some extent, in which LSS was the most critical trait. 5. Thus, the storage and transformation of NSCs under stressful conditions could reflect a dimension of long-term metabolic adaptation and cold-tolerance, which is an extension of the resource-utilization strategy beyond construction cost and growth. Our study suggested that NSCs should not be ignored in leaf economic spectrum for alpine plants.