Abstract: How to identify the facts and apply the laws is a common problem in litigation. From the aspects of strengthening the judge’s mental impression, easing the burden of proof of the parties, and ensuring the equality of arms between the parties, as a special way of fact finding, primary-face proof plays an irreplaceable role in trial practice. However, after a long period of debate, theoretical research and prejudication remain controversial on how to define thr primary-face proof, so when considering whether to introduce the system into the Civil Procedure Law of our country, there are many concerns. In order to make primary-face proof play its due function value, it should be clear on the basis of its nature, learning from foreign related theories, analyzing and combing its basic structure, so as to provide effective experience for China’s civil legislation.