This paper introduced the concept of ad-valorem equivalent tariff rate and tariff decomposition. To eliminate the impact of import price variation on the nominal tariff rate, the ad-valorem equivalent rate adjusts the specific duty to the current import price. Tariff decomposition separates the impacts of legislation and price change on the ad-valorem equivalent tariff. This paper also presents the case that the Trump 2018 Tariff had generated an overall increase in the ad-valorem equivalent tariff rate of U.S. imports for consumption. The responses to the protective tariff are different among sectors of imports.