This study purpose is to expose the strategic role of internal auditing for developing environmental performance in terms of corporate' governance. A theoretical study and review of literatures-based on form is designed consisting of four parts distributed on internal and external accounting auditors and public corporations managers. (137) questionnaire forms are distributed and (81) responses are obtained (60%). The SPSS statistical program is used for analyzing data. The study comes to these results: 1-   The public corporations are committed to known principles of corporate governance. 2-   There are no auditing committees in Libya in corporations except for banks submitted to the control of environmental criticism authority.