Abstract: The empirical laws are applied at a relatively low level in criminal justice, which is mainly reflected in the lack of effective justification. The whole purpose of applying empirical laws is to justify facts rather than finding them. Empirical laws play important roles in judging the capacity of evidence, evaluating the weight of evidence, supporting or denying the factual presumption and the attributing argumentation. The limit of the function of empirical laws determines the direction of argumentation. The empirical laws are neither substitute of evidences, nor standard of proof in criminal justice. In addition to obey the basic logic and pragmatics rules, the burden of argumentation can be assigned according to the probability and subjectivity of empirical rules, so as to reach the goal of resolving factual doubts. The effective application of empirical laws is not only conducive to the case fact finding, but also can make it into the judicial process as “good reasons”, so as to substantially enrich the sources of argument grounds and the patterns of legal argumentation.