In international trade activities, there are a variety of duties preferential system, the common ones are "the most-favoured-nation treatment", "generalized preferential system". Among them, "generalized preferential system" is the preferential system which developed countries unilaterally give to developing countries export of manufactured goods and semi-finished MFN tariffs in based on further reduction of a preferential tariff system. Since the system was implemented, in the world 27 developed countries have become the preferential system given, the benefit from developing countries and regions has reached more than 190. Due to the "GSP" is better than "the most-favoured-nation treatment", its rate is lower than MFN rates, some rates of the products within the GSP range is zero ,and this preferential is just shared unilaterally by developing countries.Therefore, China's export company can set competitive export prices according to the discount rate of the product tax rates.