99 years ago today, on November 25, 1926 (October 21, 1926 lunar calendar), physicist Li Zhengdao was born. Li Zhengdao was born in Shanghai on November 25, 1926. In 1945, he studied modern physics with physicist Wu Dayou at Southwest United University in Kunming. In 1946, he entered the research institute of the University of Chicago and received his doctorate in 1950. After a short-term job at the University of California, he worked at the Institute for Advanced Study of Princeton University for two years. In 1953, he transferred to Columbia University and was promoted to full professor in 1956. In 1960, he served as a professor at the Institute for Advanced Study of Princeton and in 1964, he served as the first Fermi Chair Professor of Physics at Columbia University. In 1956, he worked with Yang Zhenning to propose the conclusion of parity non-conservation in weak interactions. In 1957, Wu Jianxiong, working at Columbia University, confirmed their theoretical conclusions with experiments. For this, Li Zhengdao and Yang Zhenning won the 1957 Nobel Prize in Physics. After 1964, Li Zhengdao made many important contributions to the explanation of the destructive time reversal invariance phenomenon that occurs in some weak interactions. Li Zhengdao assisted the Institute of High Energy Physics of the Chinese Academy of Sciences in building electron-positron colliders and synchrotron radiation equipment, and visited China many times to give lectures. After 1980, he initiated the organization of dozens of major American universities to jointly recruit graduate students in physics in China, which contributed to the training of young Chinese physicists.