He was the first person to apply for a lawyer's practice license in the history of the Republic of China. According to statistics, in the four months from September of the first year of the Republic of China to February of 65438, Cao Rulin represented as many as 28 lawsuits, and undertook more than half of the defense work in criminal cases on appeal. From Cao Shi's practice experience, people can also get a glimpse of "the practice of lawyers as a modern profession in the embryonic stage of modernization of rule of law in China, and the meaningful social picture reflected from it".