This study investigate the relationship between internal control weakness and firm performance, and verify moderating effect of corporate governance. The sample is using non-financial listed companies in Taiwan over the period of 2004-2013. We find internal control weaknesses are significantly negatively correlated with firm performance. The results imply that firm has internal control weakness, it has lower performance. In additional, the corporate governance has positive moderating effect on the relationship between internal control weakness and firm performance, and it can improve firm performance. Our findings provide evidence that corporate governance able to effectively supervise internal control weakness and reduce the impact on firm performance of internal control weakness.