Taking Fujian Province as the research area,using the remote sensing data of land use with spatial resolution of 30m × 30m provided by the Resource and Environmental Science and Data Center in 2000,2010 and 2020,the temporal and spatial variation laws of forest land cover in Fujian Province were analyzed. And the effect of different altitude gradients on forest cover changes was studied with DEM data.The results showed that: 1) The total forest area of the study area in 2000,2010,and 2020 was 76,279.98km ²,75,807.97km²,and 75,595.75km²,respectively;the total forest area was decreasing;2) From 2000 to 2020,the center of gravity of forest land did not shift greatly;the distribution range of forest land showed a trend of expansion as a whole;in terms of spatial changes,whether it was 2000-2010 or 2010-2020,the stable area had certain advantages,with the area of about 1,200,000km²;from 2000 to 2010,the forest land loss area was 1134.78km²,and the forest land acquisition area was 662.78km²;from 2010 to 2020,the forest land loss area was 316.50km²,and the forest land acquisition area was 102.61km²;3) From 2000 to 2010,Forest land wasmainly converted with construction land and grassland,and 648.56 km² of woodland was converted to construction land,and 577.51 km² of woodland was convertedfrom grassland;from 2010 to 2020,forest land was mainly converted to construction land,and 240.47 km² of woodland was transferred to construction land;4) At altitudes <500m,both the loss and gain of forest land reached the maximum;with the increase of altitude,the loss/gain area of forest land gradually decreased,and when the altitude >2000m,the loss and gain of forest land hardly occured.