Under tariff harmonization, the United States would fall into line with the way most of the rest of the world classifies goods and services flowing in international trade.

A trade bill President Reagan signed Aug. 23 authorized United States participation in the global effort toward tariff harmonization, which has been in the works more than two decades.

Uruguay Round May Be Hurt Also likely to be affected by any trade blowup are the so-called Uruguay Round of trade-liberalization negotiations under the General Agreement on Tariffs and Trade and American efforts for tariff harmonization.