Abstract: Soil organic matter (SOM) is an indispensable component in agricultural production, playing a crucial role in enhancing soil fertility, promoting crop growth, and maintaining agricultural sustainability. Analyzing the factors influencing the spatial distribution of SOM content in cultivated land at different scales is of great significance for agricultural production management and cultivated land quality assessment in black soil regions. This study analyzes the spatial distribution patterns of SOM content in cultivated land in 2021 from both overall and regional perspectives, focusing on typical black soil region in China—Jilin Province and its three sub-areas (saline-alkali area, black soil area, and mountainous area). Additionally, the study employs the Geodetector model to quantitatively assess the explanatory power of different influencing factors at various scales. The results indicate that: 1) in 2021, the average SOM content in cultivated land in Jilin Province was 25.16 g/kg, with the mountainous area having a considerably higher average SOM content (33.58 g/kg) compared to the other two sub-areas. 2) In the saline-alkali area, the SOM content in cultivated land mainly ranged from 10 to 20 g/kg, in the black soil area it ranged from 20 to 30 g/kg, and in the mountainous area, more than half of the cultivated land had an SOM content exceeding 30 g/kg. 3) Overall, in Jilin Province, DEM was the primary factor explaining the spatial distribution of SOM in cultivated land, and the interaction between DEM and other influencing factors better revealed the spatial differences in SOM content across Jilin Province and its three sub-areas. 4) Most critical influencing factors for SOM in cultivated land in Jilin Province, as well as in the saline-alkali area and black soil area, were most significant at scales greater than 9 km, whereas in the mountainous area, they were most significant at a scale of 1 km. The findings reveal significant heterogeneity in the spatial distribution and influencing factors of SOM in cultivated land across different regions of Jilin Province at multiple spatial scales, highlighting the importance of scale-specific management strategies and providing a scientific reference for cultivated land protection and sustainable agricultural development in black soil regions.