Quantitative validation methods for carbon sequestration rates and potential of terrestrial ecosystems at the regional scale are fundamental for carbon assessment and climate change mitigation strategies. Based on future scenario data of meteorology, remote sensing, and ground observation, the DNDC model is used to assess and predict the total carbon sequestration capacity and future development trend of the forest ecosystem in Heilongjiang Province. The results show that from 2023 to 2060, the average net primary productivity (NPP) of forest vegetation in the province is projected to be(548.87 ±40.14)gC·m^-2·yr^-1, with no significant trend, peaking in 2039 at 607.18 gC·m^-2·yr^-1. The soil heterotrophic respiration rate is expected to average(293.67 ±8.71)gC·m^-2·yr^-1, showing a significant increasing trend with an average annual increase of 0.68 gC·m^-2·yr^-1. The total carbon sequestration in forests is projected to range from 82.04 to 122.23 TgC·yr^-1, with an average of(104.53 ±10.58)TgC·yr^-1, showing a moderate increase. Forest vegetation in Heilongjiang Province maintains a stable carbon sequestration capacity, yet a significant increase in soil heterotrophic respiration rates may exert long-term constraints on its carbon sink potential. These findings aim to contribute to the development of regional forest carbon balance evaluation techniques, providing insights for enhancing carbon management strategies under climate change.