Abstract: In order to reduce the effect of the inefficient use of cultivated land occupied by urban expansion on regional food security, based on GIS platform, this study combined research methods such as expansion speed, contribution index and equal fan analysis to describe the temporal and spatial pattern of cultivated land occupied by urban expansion in Chengdu metropolitan area from 2000 to 2018, and then reveal the evolution law of its utilization efficiency through BCC model. The results showed that the total cultivated land occupied by urban expansion in the study area was 470.528 km²,the expansion speed was 24.765 km²/a, and the contribution index was 74.4%, showing a trend of first strengthening and then weakening; the direction of cultivated land occupation was transferred from the west and north to the east and south as a whole; this study also found that the comprehensive efficiency, technical efficiency and scale efficiency all showed a trend of decreasing first and then increasing. In terms of the spatial change of comprehensive efficiency, the high efficiency zone moved from the central and western regions to the relatively high efficiency areas were concentrated in the northeast to southwest in the second and third periods, and the inefficient area was generally located in the west.

Key words: cultivated land occupied by urban expansion, direction change, BCC model, equal fan analysis method, spatial and temporal pattern