Reforms have been made to the modern enterprise systems of the stateowned mediumlarge enterprises of China for many years, however the reforms on the internal auditing systems of the stateowned enterprises are lagging behind, which can not meet the requirements of the social, economical and technological development. By means of analysis on the forming and development states and defects of the present internal auditing systems of the stateowned enterprises of China and analysis on the requirements for the internal auditing systems imposed by the economical and technological development, the paper expatiates on the necessity for the reforms of the internal auditing systems and provides the concepts and countermeasures for the system reforms.