Abstract: Forest carbon sequestration is an important means to deal with climate change and reduce the cost of carbon emission reduction.This paper calculated the newly increased forest carbon sink during the past 20 years through the method of accumulation expansion,and designed the situation of expanding forest area and improving forest quality to evaluate the forest carbon sink potential respectively.The results showed that the forest carbon sink continued to increase from 1999 to 2018 thanks to the increasing importance of ecological civilization construction.Under the scenario of expanding forest area,the additional carbon sink was small and not sustainable.Under the condition of improving the quality,there was still a large space to increase the carbon sink,which was more sustainable and feasible.Finally,it put forward countermeasures and suggestions from four aspects:perfecting the carbon sink measurement and monitoring system,attaching importance to forest quality improvement,promoting forest carbon sinks into carbon trading and developing forestry according to local conditions.