This paper presents a method of the association statistics between the cause of action and the statute. According to the close relationship between the cause of action and the statute in the written judgment, this paper puts forward the statistical analysis of the cause of action and the statute. The method mainly includes the pretreatment of semi-structured written judgments, reading information of the cause of action and the statute from structured documents, standardizing statutes, depositing in the database, generating EXCEL form of the association statistics from the cause of action to the statue and generating TXT form of the association statistics from the statue to the cause of action. In the process of reasoning and assessment, we can achieve the prediction of statutes and narrow the size of the cause of action.