The gaming industry is experiencing unprecedented development, the Worldwide young generation are being exposed to widespread accesses to gambling Premises, large amounts of commercial gambling advertisements can be seen everywhere, and the society in general gradually approves the legalization of gambling. With the widespread access to a variety of gambling venues and the unprecedented growth of the industry come concerns about youth gambling. What is the extent of underage gambling? How do we define underage gambling? Under which age should it be considered as underage gaming? Is it legal or illegal? What is the consideration when we deem it illegal? It should cover the issues of which legal disciplines or perspectives? What will be the consequences of underage gaming? All these problems need to be dealt with under legal system. The thesis shall focus on how to successfully regulate underage gaming. It shall introduce the general characteristics and legal features of the problem. By comparing the regulating structures for underage gaming among jurisdictions, reviewing the issue from the visions of domestic law and international law, analyzing underage gaming cross legal disciplinary, to find a way to solve the problems both in theory and in practice, therefore draw some conclusions and suggest regulatory improvements which may best harmonize the legal expectations of gaming operators and the society.