Until the eighties, Tunisia opted for a policy of import substitution and of protection of domestic market from foreign competition. Within this framework, the State controlled most of the economy such as: control of interest rates, price controls, maintaining an overvalued exchange rate, the maintenance of quantitative restrictions and tariffs high customs. In recent years, most developing countries, as Tunisia, adopt economic development strategies increasingly liberal and this by opening up their domestic markets to international trade. Indeed, the context in which the Tunisian economy is expected to move is difficult, and the challenge on its competitiveness is important. The analysis detected that Tunisia is succumbing to the foreign competition, which it faces on the world and European market. Indeed, we have revealed that Tunisian competitiveness is doped, especially, by the depreciation policy of the Tunisian Dinar and his compression policy of wages but, to a lesser extent, impelled by the real competitive potential to knowing the productivity gains. Consequently, and by the insignificant influence of structural component of the Tunisian competitiveness, it is primordial to revise its strategy of competitiveness, to be directed to the construction of a competitive potential, built on a durable basis, and un-doped by the exogenic measures, such the use of depreciation's weapon.