Abstract: Based on the data of China’s listed companies in A-share market during 2008-2012, this paper investigates the effect of the managerial overconfidence on the relationship between the accounting conservatism and the diversification of companies. The results indicate that managerial overconfidence is negatively correlated with corporate accounting conservatism; accounting conservatism can be improved in the companies with managers who are more cautious with earnings forecasts, the level of the related diversification in these companies can be further reduced. Thus, the results can verify that accounting conservatism has a governance role in correcting the behavioral biases in corporate decision-making caused by managerial overconfidence.

Key words: overconfidence; accounting conservatism; level of diversification