It is important to calculate the multi-year total of forest net primary productivity (NPP) and analyze its distribution and anomalies for evaluating and optimizing the long-term carbon sequestration function of forests. This study takes the Raohe River Basin as the research area, utilizing NPP data and land cover data to extract and overlay forest NPP information, thereby generating a spatial distribution map of total forest NPP from 2001 to 2022.Analytical methods such as the Ordinary Least Squares (OLS) model, geographic detectors, spatial statistics, and cross-tabulation were applied to investigate the spatial distribution patterns and anomalies of total forest NPP. The results showed that: (1) The decrease of forest in Raohe River Basin from 2001 to 2022 was mainly due to the occupation of cropland and construction land, while the increase of forest was mainly resulted from returning farmland to forests. Overall, the forest area in the basin showed a declining trend. (2) During the study period, the sequestration capacity of forests in Raohe River Basin was 122.20TgC, with an average total forest NPP of 12.31kgC m-2 (22a)-1, ranging from 0 to 25.49kgC m-2 (22a)-1. Among these, 80% of the forests had NPP values between 9.26 and 16.23kgC m-2 (22a)-1. Forests with land-use changes had a slight decrease in carbon sequestration capacity during the growth period. (3) The overall spatial distribution of total forest NPP in the Raohe River Basin exhibited a general pattern of higher values in the northeast and lower values in the southwest. The spatial distribution was significantly correlated (P<0.01) with the distribution of all nine factors. Among these, the influence of vegetation coverage, temperature, elevation, slope, nighttime light intensity, and soil type were stronger. and the distribution trend was consistent with vegetation coverage, elevation, slope, and precipitation, but opposite to the trends of temperature and nighttime light. (4) At the spatial scale of 500m×500m, the distribution of anomaly points was significantly affected by transportation and water system distribution (P<0.001). The influence of roads on the distribution of high-value anomalies was much higher than that of water systems, while the influence of roads on low outliers was slightly lower than that of water systems. This study investigates the spatial variation and underlying causes of forest carbon sequestration in the Raohe River Basin over a 22-year period, which can provide theoretical support and technical guidance for long-term carbon sequestration function evaluation, the identification of risk points, and sustainable development.