In recent years, the global dynamics of nonsmooth systems has aroused widespread concern both at home and abroad. Due to the nonsmoothness of the system,the classical Melnikov method is no longer applicable to studying the global dynamics. Therefore, extending the Melnikov method to the nonsmooth systems for global bifurcation and chaotic dynamics is still a difficult but hot topic. In this paper, a comprehensive review on the research progress in this field in recent years was given, especially those works on the analytical methods having advantages of geometry intuitiveness and engineering calculations. The research works by the authors on developing the Melnikov method for global dynamics of nonsmooth systems were also summarized.