| CPA express an audit opinion on accountants are part of the audit act, a direct result of the users of accounting information whether should have confidence in the financial reports of listed companies. CPA's behavior deviation impacts not only the audit market's normal development but also the healthy development of capital markets. Non-standard audit opinion is the object of concern of scholars and the public. Because it will show that the financial statements of listed companies exist in content that can not be trusted or there are some questions on listed companies'business. Non-standard audit opinion is considered increasing, however, our results have shown the impression of the public maybe not right. And fraud cases and Audit Quality Bulletins issued by Audit Commission also show non-standard audit opinion in our county is not more. And there is a question that CPA having ideas of report mistakes do not issue non-standard audit opinions still.This article studies constraint factors of CPA expressing non-standard audit opinion behavior. First we collect statistical data and the impact of the market to illustrate the status of our country's non-standard audit opinion. Second we study the factors impacting CPA's behavior, and then separately analyst the behavior through cost-benefit theory and game theory to determine CPA's possible choice and to explain status quo. Last we make policy recommendations according to the constraint factors . |