Professional identity refers to a process that answers the question "who am I" during One has been studying for years at university. The PhD is the latest stage in the development of this kind of identity that has a great bearing on the career path of individuals. The present article attempts to test the theoretical model of the PhD students' professional identity development in Iran's social sciences. The Grounded Theory of Vedadhir and Others (2017) have been operationalized and the questionnaire has been tested with participation of 191 PhD students of social sciences. Quantitative findings confirm the theatrical propositions obtained from the basic theory model. As can be seen in the above equation, Regression results show that in general, the structure of higher education, the external conditions of the social sciences, the psychological traits of PhD students of social sciences, as well as financial conditions and scientific socialization can change the dependent variable of the professional identity of the PhD degree of social sciences among respondents Better than the rest of the independent variables. The statistical results indicate that the role of external and structural factors is important.