The extension and expansion of agricultural industry chain is based on the law of agricultural development，which is integrated into such modern competitive factors as informationization，industrialization，intensification and technology，thus promoting the international competitiveness of China’s agricultural products. On the basis of classifying the situations and issues of international competitiveness of China’s agricultural products，this paper points out the necessity to vigorously extend the agricultural industry chain in China，puts forward two modes of agricultural industry chain extension——deep processing of agricultural products and innovation of science and technology，and the promoting mechanism of agricultural industry chain concerning technology innovation, knowledge management and the distribution of interests. Based on the extension of agricultural industry chain, the promotion countermeasures against the international competitiveness of agricultural products are also proposed .