The chemical structure of soil organic carbon (SOC) is crucial indicator of soil function and soil carbon stability, playing a vital role in carbon sequestration and fertility. Black soils in various regions of Northeast China encounter distinct degradation issues: Hailun region experiences decline in soil organic matter and erosion; Changchun region faces thinning of the soil; Qiqihar region suffers from loss of soil nutrients and carbon; Shenyang region deals with acidification and barrenness. The chemical structure and stability of SOC are closely associated with soil degradation. However, there is limited research on the characteristics of the chemical structure of SOC in these aforementioned regions as well as its relationship with environmental factors such as climate and soil conditions. To gain insights into the structural characteristics of SOC and its influencing factors in the black soil region of Northeast China, this study employed 13C nuclear magnetic resonance (NMR) technology to characterize the chemical structure and composition of SOC in soils from Hailun, Qiqihar, Changchun, and Shenyang regions, and further explored their relationships with soil properties and climate factors. The results revealed significant regional variations in SOC structure across Northeast China. Notably, soils from the Hailun region exhibited lower proportions of Alkyl C (30.62%±0.95%), alkyl index (A/OA) (0.96±0.06), and hydrophobicity index (HB/HI) (1.40±0.04), indicating higher chemical reactivity of organic carbon compared to other regions. Conversely, SOC in soils from the Shenyang region displayed high decomposition levels with limited breakdown potential or utilization efficiency. Negative correlations were observed between SOC, total nitrogen contents and Alkyl C proportion, A/OA, HB/HI; while positive correlations were observed between O-alkyl C proportion and Carbonyl C proportion. Moreover, the ratio of A/OA as well as HB/HI showed significantly positive correlation with mean annual temperature. These findings suggest that higher mean annual temperatures in Shenyang region accelerate SOC decomposition and thus lead to an increase in Alkyl C fraction, humification level, inertness degree, and overall stability, meanwhile, a lower reactive organic carbon content wherein. In contrast, soils in Hailun region under colder climate condition possess higher fractions of active organic carbon making them more chemically reactive. Under future warming scenarios, SOC decomposition rate in Hailun region may be further accelerated. Therefore, it is imperative to pay greater attention to monitor the dynamic of organic carbon pool, along with the implementation of measures aiming at enhancing soil carbon sequestration in this region. The findings offer a crucial reference for the accurate assessment of SOC stability and carbon cycling in representative black soil regions of Northeast China.