The processing of traditional Chinese medicine (TCM) is a unique traditional pharmaceutical technology in China, which is the most important feature that distinguishes Chinese medicine from natural medicine and plant medicine. Since the record in Huangdi Neijing (Inner Canon of the Yellow Emperor), till now, the processing of TCM has experienced more than 2000 years of inheritance, innovation, and development, which is a combination of TCM theory and clinical practice, and plays an extremely important position in the field of TCM. In recent years, as a clinical prescription of TCM, Chinese herbal pieces have played a significant role in the prevention and control of the COVID-19 and exhibited their unique value, and therefore they have become the highlight of China's clinical treatment protocol and provided Chinese experience and wisdom for the international community in the prevention and control of the COVID-19 epidemic. This paper outlines the research progress in the processing of representative TCM in recent years, reviews the mechanism of the related effects of TCM materials after processing, such as changing the drug efficacy and reducing the toxicity, puts forward the integration and application of a variety of new technologies and methods, so as to reveal the modern scientific mystery of the processing technology of TCM.