In this study, it’s argued that particularly political function among economic, social and political functions oft Trade unions . Unions political activities are essential in order to reach their goals. From this point of view, in any circumstances,unions can not be outsite of political processes. The dimensions of these relations can change in accordance with organization philosophy of trade unions. When we look at actual practices, in the world, three models are distinguishable in terms of in the relations of trade union-political party, namely “independent model”, “dependent model” and “interdependent model”. After the 1980’s, It’s observed that important changes which taken place in the relations of trade unions-political parties.