按照比较优势理论,我国应净进口粮食这一土地密集型产品。但本文在实证分析后却发现,1997年以来我国已经成为粮食产品的净出口国。粮食产品较低的“可贸易度”制约了市场机制及比较优势作用的发挥。但从中长期来看,粮食产品的“可贸易度”会呈上升态势,发挥国内外“两个市场”的作用对增强我国粮食安全保障具有重要意义。 According to the theory of comparative advantage, China should net import food-intensive land-intensive products. However, after the empirical analysis, this article finds that since 1997, our country has become a net exporter of food products. The lower “tradeability” of food products restricts the exertion of market mechanism and comparative advantage. However, in the medium and long term, the “tradeability” of grain products will show an upward trend. The role of “two markets” both at home and abroad will play an important role in enhancing food security in our country.