The decline in the quality of accounting information in the special market environment of China is a common objective phenomenon. But because of the lack of the empirical data analysis, the traditional explanations for this phenomenon are limited to some fact determination or empirical judgment. Based on such fundamental principles as knowledge constraint, hypothesis of rational man, and insider control, this paper employs a logical empirical approach to establishing the logical empirical hypothesis and logical empirical model by selecting four kinds of factual evidence, namely, knowledge, cost, interest, and collusion. Through the proof technique of logical reasoning, this paper verifies the existence of the logical empirical hypothesis, and conducts the analysis of the factors affecting the decline in the quality of accounting information and the process in which these factors operate. To directly show the shocks to the accounting quality from the affecting factors, certain models are constructed, and the conclusion of this paper is presented. Keywords: Quality of accounting information, Knowledge constraint, Hypothesis of rational man and Collusion.