China's high attention to the rule of thumb started from the "Peng Yu case" in Nanjing in 2006, whichnot only set off the moral trial and discussion of "helping and not helping" in the media, but also exposedthe chaos and disorder of the practice and application of the rule of thumb in the judicial circle. The rule ofthumb includes the general experience in the daily life of human society and the empirical knowledge in theprofessional field, reflecting the normal causal relationship between things. Because of its "experience" and"rule", the rule of experience should have both the facts and legal issues of dual attributes. In the process of findingthe facts in civil litigation, the rule of thumb also plays the functions of fact presumption, evidence evaluationand law and legal behavior interpretation. As for the rule of thumb, its extraterritorial application is earlier andmore mature than that in China. The apparent proof in German law, the "approximate presumption" in Japaneselaw and the "self-evident" principle in Anglo-American law all show that the rule of thumb plays an importantfunction in extraterritorial litigation fact finding. In the judicial practice of our country, there are two types ofrule of thumb: missing and wrong application, which is due to the probability and subjective disadvantages ofrule of thumb itself, and the cognitive bias caused by individual differences of judges. Of course, it also reflectsthe legislative deficiency related to rule of thumb in our country. Therefore, our country should fully explainthe selection and application of the rule of thumb in various judgment documents on the basis of the disclosureof the judge's heart evidence, initially explore the segmented trial mode, and build the rule of thumb appealrelief mechanism, in order to achieve the standardization of the application of the rule of thumb, promote thenormalization and effectiveness of the identification of facts, and realize the unity of the application of law.