With global warming and the sea ice melting, the Arctic Ocean ecosystem is undergoing significant changes. Phytoplankton light absorption and primary productivity are important parameters of marine ecosystems. The long-term evolution characteristics of the phytoplankton light absorption and primary productivity were analyzed with long-term satellite observation datasets. It was found that in the past 20 years, the phytoplankton light absorption increased in nearly 66% of the Arctic Ocean, and the area of light absorption dominated by phytoplankton has increased significantly. In this context, the primary productivity of the Arctic Ocean has increased significantly. On this basis, the mechanisms of sea ice construction, sea surface temperature, mixed layer depth and runoff were analyzed. It was found that the continuous melting of sea ice, the rise of sea temperature and the deepening of mixed layer depth were the main reasons for the enhancement of phytoplankton light absorption and primary productivity. This study reveals the evolution characteristics and driving mechanisms of phytoplankton light absorption and primary productivity in the Arctic Ocean, and lays a foundation for understanding the evolution of Arctic Ocean ecosystems in the context of climate change.