E-commerce is an innovative new form of trade in goods and services, whose emergence and development is the result of the advancement of new technologies and reflection of the new knowledge-based economy. This new trade mode indicates that the existing international tax regime should be reexamined. Since the legal regulation of e-commerce started late, researches on international e-commerce legal issues is not mature enough, and it is particularly reflected in the e-commerce tax law. By consulting a lot of materials in domestic and overseas, I make an in-depth study and exploration on cross-border e-commerce tax law issues, based on international tax law principles and theories. E-commerce is conducted in the unique environment of network. It takes place in a virtualization platform, which is known as Internet or cyberspace. The transactions in e-commerce are paperless－all the contracts and relevant documents between transacting parties are in electronic form. The matters dealt with in e-commerce transaction could be tangible goods, intangible goods and online services. The transaction is anonymous to some extent－the non-face-to face transactions occur in e-commerce and therefore both sides of the transacting parties may not know each other. In addition, the transaction is conducted by online payment system, thus the process and the results of the transaction will have no physical records for audit trail. E-commerce has the characteristics of being global, virtual and anonymous, which makes some existing rules and principles of international taxation less effective. The current tax jurisdictions consisting of source-based taxation and residence-based taxation have been challenged and the tax jurisdiction conflict has increased. In the meantime, the concept of “permanent establishment” in international taxation warranted redefinition since it is a concept based on physical presence of business activities in traditional economy. The transactions conducted by e-commerce especially e-commence in digital products makes the income classification rules 5 unworkable and creates confusion when state seeks to tax the income generated from them. The Internet provides convenience for international tax avoidance, and in the context of cross-border e-commerce, the tax avoidance phenomenon take on new forms. E-commerce as a new type of economic activity doesn’t have a robust taxation system to regulate. Currently, there is no country that could design a tax system to solve the problem of taxation on cross-border e-commerce all by itself because it’s a global issue. Without considerable international consensus, the phenomenon of jurisdiction conflicts and double taxation or tax avoidance will prevail and the international tax system will falter. For ease of regulation, it is necessary to unify the basic theory. This thesis examines the difficulties and challenges in applying the current international tax rules to cross-border e-commerce activities and the risk of jurisdiction conflict and tax avoidance. The international community calls for a global consistent approach to tax these new activities. It is of vital importance to reach an international consensus on e-commerce taxation issues. The establishment of international standards is indispensible to cope with the emerging issues and challenges.