Six Sigma is known as the best quality management system, which has been applied in different places with distinct tasks. Any implementation of Six Sigma project normally can succeed only when human resource management is applied within the organization, properly. In this paper, we illustrate the intense of relationships between the human resources management indices and Six Sigma project implementation indices for some selected Iranian manufacturing firms. By using the fuzzy cognitive maps (FCM), we are able to show the strength of relationships among various indices. This study helps quality and human resource managers learn how to manage the critical indices to achieve their determined goals and to increase Six Sigma project performance throw human resource management perspective.