Abstract: Based on calculating the dynamic change of land, population, grain output in 2000 -2011 by using MATLAB software, change characteristics of cultivated land area, population and the pressure index of cultivated land in Guizhou province were analyzed, and DGM (1,1) discrete model was used to forecast the cultivated land pressure index in 2015-2030. The results showed that the total cultivated land and per capita area of cultivated land continued decreasing, but the net outflow of population accelerated, at the same time the per capita grain output continued increasing, the cultivated land pressure index volatility reduced, cultivated land pressure index kept above 1.0, food supply was unsafe in Guizhou province in 2000-2011. The cultivated land pressure index will continue to reduce and the food security situation eases in 2015-2030. The result indicates that it is the basic way to reduce the pressure of cultivated land and ensure food security by increasing the agricultural investment in science and technology, strengthening the basic construction of farmland and land rectification work, speeding up the net outflow of population