Abstract: Based on the cost-income data of agricultural product and relative agricultural statistic data during the period 1980～2005, the paper has discussed the characteristics of peasant household cultivated land use behavior in metropolitan suburb, the according land use changes and it’s effect on grain productive capacity taking Beijing as an example, The results show：peasant households would like to implant more cash crops which has topper intensive margin, such as watermelon, vegetable, which is the most important characteristic．And some would choose extensive land use pattern. Land use change has presented that the sown areas of grain crops in Beijing increased, then decreased, and the intensity index is also low．Because land use objectives of peasant household have stage-changed, at first seeking for grain production maximization, then seeking for optimization of grain production and profit, at last seeking for profit maximization. The peasant household choice will of grain crops increased, and then decreased, which has a great impact on cultivated actual grain productivity. At last, the paper analyzed grain yield per hectare of every county in Beijing from 1978 to 2005, which has also stage-changed.