Abstract: American agricultural subsidy has experienced five stages’ development, i.e. gestation, generation and development, reducing, adjustment and new development. And it has features as follows: the amount of subsidy investment is huge; the “yellow box” policy accounts for large proportion; it focuses on main farm products and latifundia; the relevant laws, regulations and auxiliary support policy are sound; the preliminary work is done very well; it is corrected and adjusted timely and focused on environmental protection and food safety. Therefore, it has some positive effects, such as dealing with agricultural production risk, eliminating the worries of farmers, improving international trade competitiveness of agricultural products, expanding the international market, developing modern agriculture and promoting sustainable development, etc. But undeniably, American agricultural subsidies fall into vicious circle, which leads to increasing the financial burden of the government, using land excessively, destroying the environment, exacerbating the gap between rich and poor farmers, reducing the “immune” ability of farmers and triggering the international trade friction, etc. This study offers Chinese agricultural department with some useful revelations in terms of clearing goals of subsidies, forming subsidy system, perfecting subsidy mechanism, enhancing the capability of sustainable development, balancing between the efficiency and fairness and transforming from “yellow box” to “green box” policies, etc.