【Objective】 To ensure the sustainable development of agriculture, this study aimed to clarify the temporal and spatial changes of soil organic matter, bulk density, and driving factors for Nenjiang City's “thinning and hardening” list. 【Method】 Nenjiang City is located in the core area of typical black soil distribution in China. In 2023, a field survey was conducted at the same locations as the Second National Soil Survey to reassess the current soil conditions. The key soil properties measured in this study included soil organic matter, bulk density, and other physicochemical characteristics at two soil depths(0-20 cm and 20-40 cm). The "point-to-point" method was used to visually reflect the spatiotemporal changes in soil properties over the past 40 years. Furthermore, correlation analysis and redundancy analysis were employed to explore the factors influencing the changes in soil organic matter and bulk density in Nenjiang City. 【Result】 The distribution of soil organic matter and bulk density in Nenjiang City showed significant spatial differences. The organic matter was higher in the east and lower in the west, and the bulk density was higher in the southwest and lower in the northeast. The results showed that in the past 43 years, with the intensities of human activities such as agricultural production, the organic matter content of cultivated soil in the Nenjiang black soil area showed an overall decreasing trend, with that of the surface decreasing by 11.89% and the subsurface by 6.99% compared with 1980. It was observed that locations initially having higher organic matter content experienced a significant decline. In addition, the bulk density of cultivated land in the Nenjiang black soil area showed an overall upward trend, with that of the surface increasing by 12.14% and the subsurface by 17.09% compared with 1980. In different soil types, the decline in average organic matter content was the greatest in black soil, while the average organic matter content in meadow soil increased. At the same time, the average bulk density increased across all soil types, with the greatest increase observed in dark brown earth. In addition, among the factors influencing soil organic matter, total nitrogen, tillage layer thickness, total phosphorus, and slope were all positively correlated with changes in soil organic matter. Among these, total nitrogen and total phosphorus showed the strongest correlation with organic matter variation. On the other hand, changes in soil bulk density were more strongly influenced by clay content, climatic factors (effective accumulated temperature and annual precipitation), and topographic factors (slope). 【Conclusion】 Based on the above results, the changes in soil organic matter and bulk density in Nenjiang City are influenced by multiple factors, including soil properties, climate, and topography. Future efforts should focus on addressing issues such as soil fertility improvement and the elimination of plowpans in the southwestern part of Nenjiang City.