In the first part of this paper some theoretical problems are discussed. They include the definition and actural content of sustainable agriculture, the relation between development and environment, the merits and wrongs of modern agriculture,the traditional and modern technology and so on. The unification of productional, economical and ecological sustainment is emphasized.In the second part some practical problems concerning Chinese agriculture are discussed. They are the direction and ways of agricultural development, the problems faced and the target of Chinese agriculture in the 21st century-agricultural modernization. The intensive sustained agriculture is recommended.