Objective This study aims to analyze the impact of spatiotemporal changes in land use patterns on regional carbon storage in Heilongjiang Province， predict future evolution under multiple scenarios， and quantitatively identify the main driving factors of spatial differentiation in carbon storage. Methods Based on four periods of land use data in Heilongjiang Province from 1990 to 2020， the PLUS-InVEST-Geodetector model was coupled to analyze changes in land use patterns and their carbon effects. Future land use and carbon storage in 2060 were simulated under four scenarios： Natural development， cultivated land protection， ecological protection， and urban development. Results From 1990 to 2020， carbon storage in Heilongjiang Province showed a net decrease of 53.46×10⁷ t， with a spatial pattern of high in central regions and low in surrounding areas， high in the north and low in the south， and high in mountainous areas and low in plains. The conversion of forest land to cultivated land， grassland， and unused land was the primary pathway for carbon loss. Multi-scenario simulations indicated that carbon storage in 2060 followed the order： ecological protection scenario （2 012.71×10⁷ t） > natural development scenario （2 000.59×10⁷ t） > urban development scenario （1 996.01×10⁷ t） > cultivated land conservation scenario （1 992.08×10⁷ t）. Geodetector analysis revealed that the spatial differentiation of carbon storage was mainly influenced by factors such as elevation， distance to water bodies， and normalized difference vegetation index （NDVI）. Interactions among factors were mainly characterized by two-factor enhancement and nonlinear enhancement， with the strongest interactions observed between digital elevation model （DEM） and annual precipitation， DEM and distance to rivers， population density and DEM， and DEM and NDVI. Conclusion During the historical period， the conversion of forest land to cultivated land and grassland in Heilongjiang Province led to a continuous net decrease in carbon storage. Future projections indicate that carbon storage is the highest under the ecological protection scenario， with factor interactions centered on DEM dominating the spatial differentiation of carbon storage. Therefore， it is necessary to control the conversion of land types with higher carbon density to those with lower carbon density， strictly implement black soil protection policies， and adopt ecological protection measures. The impacts of natural and socio-economic factors should be comprehensively considered when formulating regional ecological protection and economic development policies， so as to promote the sustainable development of the regional economy in Heilongjiang Province.