Recently, environmental, social, and governance (ESG) has become a new paradigm for corporate management and investment as a global trend. In particular, the board diversity is being emphasized as a standard related to the corporate governance of ESG. In a broader sense, the board diversity includes race, gender, nationality, and sexual orientation, and in a narrow sense, the board diversity focuses on gender diversity, among which female directors are a key issue. In this regard, while some countries implement a female director quota system that forces the appointment of female directors, others implement a system that entrusts the appointment of female directors to the autonomy of companies. In general, the board of directors is a main body in a company's business decision-making, and the responsibilities of directors who are members of the board of directors are gradually expanding. Since there is an important relationship between corporate governance and sustainable growth, the issue of the board diversity has become an important concern for long-term investors. There are a number of empirical studies that say that expanding the number of female directors can improve the monitoring and supervision functions and decision-making functions of the board of directors and can improve corporate management performance through changes in corporate culture. In other words, it can be evaluated that there is a correlation between securing gender diversity and improving corporate management performance or corporate governance in the board diversity. From this point of view, in order for listed companies in China to further grow into a global company, it is necessary to pay more attention to securing the board diversity, such as expanding the number of female directors, and the Chinese government needs to strengthen policy support on the board diversity. In conclusion, the following institutional improvement measures should be taken to improve the board diversity of Chinese companies. First, it is necessary to promote policies that provide internal motivation for the board diversity for Chinese companies. For example, in most companies, it is necessary to implement policies to promote the appointment of female directors because the board diversity is insufficient. Second, it is necessary to promote policies to improve the quality of information disclosure by Chinese companies regarding the diversity of the board of directors. In addition to promoting the introduction of a mandatory disclosure system, it is necessary to develop qualitative and quantitative disclosure indicators. Third, there is a need to improve the evaluation model for the diversity of the board of directors and ESG of Chinese companies. The ESG evaluation model needs to be improved by incorporating long-term practical experience. In order not to neglect the diversity of the board of directors, it is necessary to delegate the evaluation to a more specialized institution such as the Women's Federation to summarize the experience and use it to improve the overall evaluation model. Fourth, it is necessary to establish a regular exchange platform between mainland China and Hong Kong so that companies can share and learn experiences and examples of ESG practice between companies in various aspects