‎Copula functions as a model can show the relationship between variables‎. ‎Appropriate copula function for a specific application is a function that shows the dependency between data in a best way‎. ‎Goodness of fit tests theoretically are the best way in selection of copula function‎. ‎Different ways of goodness of fit for copula exist‎. ‎In this paper we will examine the goodness of fit tests from theoretical point of view and evaluate three different methods for comparing the copula functions as well as numerical comparison in order to show the advantage and weak points of each method‎. ‎At the end we will analyze the methods of discussed test by using the information from Tehran Stock Exchange‎.