Charateristics and causes of foreign trade deficit of agricultural product are very important for the making and implementation of China’s policy in expanding agricultural opening to the outside world.Based on China’s promises made in market-access negotiations of agricultural products and data from China’s Customs and United Nations Commodity Trade Statistics Database,this paper concludes that China’s sustaining deficit in agricultural trade originates from its absolute weakness in the endowment of agricultural resources and an all-round strategy of opening agriculture; the drastic increase of the importation of genetically-modified products,such as cotton,soybean,is reinforcing the deficit; as a large agricultural nation,China will continue to be in a position of trade deficit for a long time,and the key measures to cope with the grave situation are to optimize the structure of agricultural opening and to design a package of policies which can expedite agricultural development,ensure agricultural security,and mitigate the possible unfavorable impact of increasing agricultural trade deficit.