47 years ago today, on May 10, 1978 (April 4, 1978 in the lunar calendar), "Practice is the only criterion for testing truth" was published. The 60th issue of Theoretical Dynamics, an internal publication of the Party School of the Central Committee of the Communist Party of China, published the article "Practice is the only criterion for testing truth". On May 10, 1978, the 60th issue of Theoretical Dynamics, an internal publication of the Party School of the Central Committee of the Communist Party of China, first published the article "Practice is the only criterion for testing truth" approved by Comrade Hu Yaobang. On May 11th, Guangming Daily published a special commentator's article entitled "Practice is the only criterion for testing truth". On the same day, Xinhua News Agency forwarded this article. On the 12th, People's Daily and People's Liberation Army Daily reprinted it at the same time. This paper discusses Marxism-Leninism's viewpoint of practice first, and correctly points out that any theory should be tested by practice. The theory of Marxism is not a pile of stiff dogmas, but it should constantly add new contents in practice. Of course, there is still a false tendency that "what is uploaded in the Bible is right". This is the spiritual shackle imposed on people by the Gang of Four, and it must be resolutely broken. This article sparks discussion on the issue of practice as the only criterion for testing truth. The vast majority of people inside and outside the party support and support the views of the article. Although Hua Guofeng instructed some leaders of the central propaganda department to "not express their position" or "not get involved" in the discussion of the standard of truth; On some occasions, Wang Dongxing accused this article of "actually pointing the finger at the chairman's thoughts" and asked, "Which central opinion is this?!" To suppress it. However, this discussion was actively supported by Deng Xiaoping, Ye Jianying, Li Xiannian and Hu Yaobang of the CPC Central Committee, and the discussion was gradually carried out throughout the country. From June to November, the main responsible comrades of various departments of the central party, government and army, and most provinces, municipalities, autonomous regions and major military regions across the country published articles or speeches, and unanimously believed that adhering to the Marxist principle that practice is the only criterion for testing truth is of great practical significance. This discussion broke through the serious shackles of "two whatevers", promoted the nationwide Marxist ideological emancipation movement, made important ideological preparations for the epoch-making Third Plenary Session of the Eleventh Central Committee of the Party, and had a significant and far-reaching impact in the historical process of the Party and the country. Guangming Daily published "Practice is the only criterion for testing truth" in the name of a special commentator.