本論文以 2009 至2011 年中國上海及深圳上市A股公司為研究樣本，探討內部控制品質、法律環境與盈餘平穩化之間的關聯，本論文採用中國財政部與深圳迪博企業風險技術公司共同研究建立的上市公司內部控制指數來衡量企業之內部控制品質。本研究並進一步探討，中國市場法律環境與盈餘平穩化之間的關係。實證結果發現，中國上市公司之內部控制品質越好，其管理當局藉由盈餘管理使盈餘平穩化之程度越低。亦發現公司所在地市場法律環境發展程度高，律師人口比率高的地區，因可能遭受訴訟的風險增加，管理階層越會利用損益平穩化之方式進行盈餘管理。 / This thesis investigates the relationship between internal control、legal environment and income smoothing. The research sample is based on all listed China companies in Shanghai and Shenzhen Securities Exchange during 2009-2011. First, The empirical results show that the internal control quality is significantly related to income smoothing. It indicates that smoothing earnings is more prevalent for firms with poorer internal control quality. Next, the development of the area legal environment (population of lawyers) might influence the litigation risk of firms with income smoothing behaviors. Therefore, I further investigate how the extent of legal environment would influence the behaviors of income smoothing. The research results show that the extent to which legal environment development is significantly related to income smoothing behaviors. It means that managers are more likely to smooth earnings to reduce the litigation risk when the extent of legal environment development is high.