Under climate change, the quantitative assessment of the net primary productivity (NPP) and ecological service function of the forest ecosystem in China is of great significance for the correct evaluation on the forest role in the ecological environment construction in China. Taking the forest ecosystem in China as the research object, using the remote sensing data and the China' s forest ecosystem carbon sequestration model FORCCHN, we simulated the net primary productivity NPP of forest ecosystem in China in 19812017, and evaluated its carbon sequestration and oxygen release ecosystem services function. The results showed that, (1) from 1981 to 2017, the annual changes in the unit area NPP and the total NPP in China' s forest ecosystems showed obvious increasing trend. Especially, the total NPP fluctuated between 2.02 Pg·a~(-1) and 2.53 Pg·a~(-1), with an average of 2.36 Pg·a~(-1). The maximum total NPP and the minimum total NPP were found in 2004 and 2010, respectively. (2) The interdecadal increase of NPP was also obvious. The most significant increase was found between 2000s and 2010s. (3) The basic characteristic of the spatial distribution of NPP was high in the south and low in the north. In the recent 36 years, the difference in increased NPP per unit area of forest ecosystem was significant in different regions. Among them, the most obvious increase inper unit area NPP was found in the southwestern forest, with the maximum increase of more than 666.7 g·m~(-2)·a~(-1). As for the southeastern forest, the maximum increase inper unit area NPP was more than 444.4 g·m~(-2)·a~(-1). (4) In the recent 36 years, the carbon sequestration value and oxygen release value of forest ecosystem in China fluctuatly increased. The total value of carbon sequestration and oxygen release was 140 883.27*10~9 yuan. Moreover, the value of releasing oxygen was 2.82 times of carbon sequestration value.