In an era of globalization today, more and more companies try to internationalize since they are aware of the importance of internationalization on the growth and expansion of their capacity and resource generation. In the attempt to create an overall picture of what the process might be, the paper provides a set of basic information of a firm's internationalization process, including the most prevailing definitions of the process, advantages a firm can gain from internationalization, the model of internationalization, determining factors for a firm's internationalization, and obstacles preventing firms from internationalizing.