The article explores how accounting practices have evolved in China's listed companies in relation to investor protection and changes in the capital market system. Before 2007, accounting conservatism improved as investor protection increased. However, after 2007, new accounting standards reduced the significance of accounting conservatism. The expansion of fair value accounting may have had a negative impact on conservatism. The study suggests that when revising accounting standards to enhance information relevance, other aspects of accounting information quality should also be considered. Improving accounting information quality requires not only reforming accounting systems but also strengthening legal, corporate governance, and infrastructure systems.