基于不同保护目的的最优关税分析

从不同的保护目的出发，可将最优关税区分为最佳福利关税和最大收入关税。假定一个国家自身生产一种产品，同时进口另外一种产品，且两种产品的质量不同，分析最佳福利关税和最大收入关税问题，结果发现：第一，如果本国的产品质量较低而进口的产品质量较高，那么，无论企业之间是进行Bertrand竞争还是Cournot竞争，假如国外企业的效率较高（低），那么最大收入关税大（小）于最佳福利关税；此外，Cournot竞争条件下的最佳福利关税和最大收入关税分别高于Bertrand竞争条件下的最佳福利关税和最大收入关税。第二，如果本国的产品质量较高而进口的产品质量较低，那么当本国企业的效率较低（高）时，最大收入关税高（低）于最佳福利关税。

Analysis of Optimal Tariff Based on Different Protective Targets

On the basis of different protective targets, optimal tariff can be classified into optimal welfare tariff and maximum revenue tariff. If a country itself produces a product and imports another product, the quality of the two products is different, we can analyze the issue of optimal welfare tariff and maximum revenue tariff, the analysis results show that, on the one hand, if the domestic product quality is relatively lower but the imported product quality is higher, no matter Bertrand competition or Cournot competition the enterprises conduct, then maximum revenue tariff is larger (smaller) than optimal welfare tariff if foreign enterprise efficiency is higher (lower), furthermore, the optimal welfare tariff and maximum revenue tariff under Cournot competition condition are higher than optimal welfare tariff and maximum revenue tariff under Bertrand competition condition respectively; on the other hand, if domestic product quality is higher but the imported product quality is lower, then maximum revenue tariff is higher (lower) than optimal welfare tariff if domestic enterprise efficiency is lower (higher).