Abstract: The fairness of the public policy is the cornerstone of its rationality and feasibility. This paper, based on the study of the mathematical model of the fairness issue of China's housing accumulation fund system, proposes a set of exploratory policy fairness concept system, evaluation system, and its corresponding mathematical model system, and tries to give the intuitive expression of fairness through the concept and the calculation model of policy fairness, policy benefit level, policy benefit variation, etc. This system makes a quantitative analysis and qualitative judgment on a series of fairness issues existed in history and in current China's housing accumulation fund system, and puts forward the improvement direction and improvement method according to the inherent laws revealed by mathematical and physical sciences.