Abstract: At present, in the theoretical and practical fields in China, there are some contradictions and omissions in the understanding of the connotation and attribution of "Law of Immediate Application", and there is a lack of clear exposition of its application as well. Based on the related theories, attribution, the way of adjustment and some other aspects of "Law of Immediate Application",it should be defined as specific legal norms and articles in some domestic substantive law. "Law of Immediate Application" is neither public law nor private law, but it should be recognized as an attribute of economic law. As for its practical application issue, as the value and legitimacy of "Law of Immediate Application" are largely based on the pursuit of substantial justice. In individual cases, it should be applied by the judge in accordance with the terms of reference and discretion, and it should be determined by substantial judgment.