The response of treeline trees to climate warming is highly complex. Although numerous studies have examined this issue worldwide, comprehensive coverage of all global treelines remains impossible, and the roles of temperature and precipitation exhibit pronounced spatiotemporal variability. To address these gaps, we collected tree-ring samples from two Picea species at treeline sites in the Helan Mountains (western China) and Luya Mountain (central China) along the same latitude, and conducted dendroclimatic analyses. Correlation analyses revealed that in the Helan region, growing-season temperatures had a significant negative influence on tree growth before 1998, after which precipitation became the dominant positive driver. SPEI-based analyses showed significant positive correlations between ring width and multi-month SPEI from June to August, indicating that tree growth at the Helan treeline was moisture-limited. In contrast, tree growth at the Luya site was consistently and positively correlated with May temperature, with no significant relationship to precipitation. Analyses using SPEI further demonstrated that moisture is not a limiting factor for tree growth at the Luya treeline. Our findings suggest that macroclimate is likely governing how treeline trees respond to climate variability. Under continued warming, arid regions may experience growth decline due to intensified drought stress, whereas humid regions are likely to benefit from rising temperatures. These results contribute to the global dataset on treeline responses to climate change and provide clear evidence for the relative roles of temperature and moisture in governing treeline dynamics.