Due to insufficiency and asymmetry of information, the plaintiff are often unable to prove the economic loss or profit the defendant may get in the patent infringement litigation. Statutory damages is often adopt by the court. From the perspective of behaviorism, this paper makes an empirical study of 198 judgments using multiple regression analysis. It is found that some non statutory facts, such as patent complexity of technology, economic strength of the defendant would influence the judges This is a challenge on legal dogmatic in the field of patent infringement, which reveals the decision process of the judges, and provides beneficial enlightenment on management and decision in patent application and litigation.