Abstract: A model was set up based on Cournot quantity competition between foreign firms and local firms in considering import taxes. Through this model， the effect of the fixed-fee， royalty and two-part tariff licensing modes on the profit of foreign firms and the social welfare of import countries was analyzed to explain the mechanism of technological licensing in the transnational context. The research showed that the fixed-fee mode may make the profit of foreign firms uncertain and damage the social welfare of import countries. Royalty mode can increase the profit of foreign firms while it may decrease the social welfare under certain conditions. The two-part tariff mode can increase the profit of foreign firms and the social welfare， which realizes both the corporate and social goals. Morover， the two-part tariff mode may be specialized into the fixed-fee mode when the import tax is comparably high.

Key words: transnational licensing, import tax, cost-reduction technology, Cournot competition, social welfare