「二重證據法」的歸納是中國近現代學術史上一個非常著名的事件，他影響了整個二十世紀的中國學術研究和學術史。舉凡歷史學、哲學、考古學、文學、語言文字學等傳統學科，無不以二重證據法作為自己的新思想和新方法。「二重證據法」是指用地下出土文獻與地上傳承文獻相互印證的研究方法，又可以叫新見材料與傳世文獻互相印證的方法，用不同的方法指向同一個研究的問題。上個世紀初，甲骨文、簡牘、敦煌遺書、大內檔案、中國境內之古外族遺文被稱為五大發現，王國維等學者運用這些新材料，證明了古史上的若干史跡。後來，學術界自陳寅恪始，均以為「二重證據法」是王國維發明的。但王國維本人卻不以為是從他開始的，即「中國紙上之學問賴於地下之學問者，固不自今日始矣」。 文章通過梳理二重證據法的「源」和「流」，對二重證據法產生的歷史背景和提出進行了研究，認為二重證據法肇始於上古。界定了二重證據法的廣義與狹義，認為這裏的證據是「新材料」而並非僅僅是甲骨文。文章臚列了唐以前和宋以後發現的新材料，前人將這些材料與傳世文獻之間比照考據情況，以及顧炎武、錢大昕、劉師培等人的理論歸納。大量的證據表明，二重證據法無論從理論歸納還是文獻考據實踐，都不是從王國維開始的。古代早期如漢代司馬遷、劉向、許慎，中古如顏之推、劉知幾、歐陽修、趙明誠、洪邁、鄭樵，近古如楊慎、顧炎武、段玉裁、阮元以及現代傅斯年、陳寅恪、顧頡剛等學者，都運用了二重證據法。通過歷代學者對二重證據法的實踐和論述，這裏還發現二重證據法並不是單向的以出土文獻證地上文獻，而是地上、地下互相證明的雙向過程。不僅如此，地下與地下亦可相互為證。文章論述了現代學術中二重證據法發展為三重證據、四重證據，二重證據法在當代學術中的重要性及應用；甚至對歷代的一些學術定論，例如辨偽學的某些結論也因為二重證據法的出現而需要重新論證。文章通過研究，對二重證據法的本質特徵做出科學的歸納，即多學科綜合互證。

The induction of dual attestation constitutes a vital part in Chinese modern academic history, which has great impact on Chinese academic research and history of the whole 20th century. For example, traditional disciplines such as history, philosophy, archaeology, literature，linguistics, etc, all take dual attestation as their new ideology and method. Dual attestation means making mutual verification by comparing the excavated documents and that handed down from ancient times, and it can also be called confirmation between the traditional documents and the new founded ones, that is, shooting at the same research subject with different methods. At the beginning of last century, the top 5 findings, including inscriptions on oracle bones, bamboo slips, Dunhuang ancient writings, Working files, and ancient writings by foreign clans in ancient China were used by scholars like Wang Guowei to prove the existence of some ancient relics. Afterwards, starting from Chen Yanke, the academic circle has been considering Wang Guowei the founder of dual attestation. However, Wang Guowei didn't impose himself as the pioneer of dual attestation, just like he said “The Chinese scholarship derives from our late ancient scholars instead of today’s. ” By combing the source and course of dual attestation, this thesis makes a study on the historical background of emergence of dual attestation and concludes that dual attestation dates back to the antediluvian times, defines it in both broad and narrow senses by putting forward that the attestation is not only inscriptions on oracle bones, but the New Documents. It lists all new documents founded before Tang Dynasty and after Song Dynasty which are made comparison with the traditional documents by former scholars, and makes an induction of theories by Gu Yanwu, Qian Daxin and Liu Shipei, etc. Abundant evidence manifests that, no matter in theoretical induction or documents study, Wang Guowei is no pioneer of dual attestation.In the early peroid of ancient times, there were Sima Qian, Liu Xiang and Xu Shen in Han Dynasty, later in the middle came Yan Zhitui, Liu Zhiji, Ouyang Xiu, Zhao Mingcheng, Hong Mai and Zheng Qiao, and after which,Yang Shen, Gu Yanwu, Duan Yucai and Ruan Yu dominated the latest peroid of the ancient, and in the modern times, scholars, such as Fu Sinian, Chen Yanke, Gu Jiegang, etc, all put this theory-dual attestation-into application.Through the application and interpretation to dual attestation, here is another finding that it is not only confirmation of overground documents and relics against underground unearthed documents, but also the mutual verification between the two. In modern academy, dual attestation has developed into triple attestation or even quadruple attestation, and it has not only played a significant role in modern academy, but also promoted the advance of some academic conclusions of all ages, for example, some of conclusions of detection of forgeries need to be verified due to the emergence of dual attestation. This thesis, through thorough research and analysis, made a scientific induction to the substantive characteristics of dual attestation, that is, multidiscipline and comprehensive mutual attestation.