Today, it is very important to pay enough attention to managerial competencies of managers, especially to public sector human resource managers, who are responsible for implementing the Management By Competency (MBC) system in Iran’s public sector .This paper proposed a heuristic model which is composed of some variables like Intelligence Competencies (IC), Managerial Competencies (MC), Human Resource Managers Competencies (HRMC) and Human Resource Value Proposition (HRVP), based on studying different competencies model and research results in the field of human resource competencies and using focus group method. Then extending competency issues from private sector to public sector, is considering as one of the most important issues in this research. After constructing of questionnaire based on designed model and testing its validity and reliability, we distributed it among some human resource’s experts and managers of Iran’s ministries, as statistical sample. This research is a descriptive-exploratory & qualitative-quantitative, one which its hypothesis are tested by Structural Equation Modeling (SEM). The results of this research show that (IC) affect (MC) & (HRMC) and (MC) affect (HRMC). It is also shows that only (HRMC) has an influence on (HRVP).It should be mentioned that among 56 indexes relating to variables, “Heeding moral principles”, among 14 observed variables “Planning and Administrative Competency” and among four latent variables “Human Resource Value Proposition” have the first priorities.