Cropland potential productivity in Sichuan Province is estimated by soil quality index. Most soil quality index is less than 0.70. The area of the first, second and third grade cropland is 185 447 ha and accounts for 42.5% of the total cropland in Sichuan, and the area of the fourth grade and others grade with low yield makes up more than 50% of the total (the second time general investigation of soil resource of China). The climate-soil productive potentiality of Sichuan are 10.7?10¹⁰ kg and 69.8? 10⁹ kg with the area cited from the second time general investigation of soil resource of China and statistic of 2001, respectively. According to the climate-soil productive potentiality of Sichuan, the food supply will fail to meet the people's need and will lack 52.4?10⁸ kg and 16.8?10⁷ kg using the linearity model and the exponent model to forecast the population and the area of cropland in 2040, the population of 3863400-12012000 will suffer from shortage of food. If using the actual production capacity to calculate, it is concluded that the population bearing capacity will be overloaded from 2000.In the next 50 years, 8874259-29822803000 kg of grain will be short and the population of 203654000-68401000 preson will be overloaded in Sichuan Province. The result showed that overloaded population-bearing capacity and the shortage of food will not be avoided and the situation will also be austere.