In the Arctic Ocean, phytoplankton are highly influenced by sea ice conditions and brine release. Phytoplankton dynamics are subject to the timing of nutrient and light-dependent biological production. Fram Strait (located between Svalbard and Greenland) as an important gateway to the Arctic, is a region where the cold ice-covered Arctic water exits from the western side and the warm Atlantic water enters the Arctic Ocean through the eastern side of the Strait. The two contrasting water masses interact in the central Fram Strait leading to complex phytoplankton dynamics especially under a rapidly changing Arctic climate. Within the framework of the Copernicus Marine Service Evolution Program, we have generated global chlorophyll a products of several phytoplankton functional types (PFTs) derived from multi-sensor ocean color data, for a consistent long-term monitoring of the surface ocean PFTs. The two-decade observations enable us to study the inter-annual variation and analyze the trend of the surface phytoplankton community structure on different scales. Focusing on the Fram Strait, we first perform a gap-filling method to reconstruct the satellite PFT products for Arctic waters, then evaluate the reconstructed PFT observations using in situ data from AWI established LTER Observatory HAUSGARTEN area, which includes data sets of bio-optical properties, pigment composition, phytoplankton taxonomic data from expeditions in the past years. We further investigate the current state and the two-decade trends of the major PFTs; present and interpret their phenological patterns, inter-annual changes and the potential connections between the PFT shifts/trends and climate drivers in the Fram Strait.