Authenticity is key to maintaining the domestic brands’ native characteristics after internationalization. This paper aims to discuss the difference in brand authenticity before and after internationalization and probe into its influence on consumers’ purchase intentions. Based on brand authenticity theory, we propose a theoretical model of relationship among brand authenticity, consumer ethnocentrism, purchase intention, and corporation force. Then it tests the model empirically with the method of Hierarchical Regression Modeling. Based on the data collected from 377 participants, we draw some conclusions. Firstly, the degree of brand authenticity decreases significantly after internalization. Secondly, the more power the domestic brand has during corporation, the more authentic the domestic brand is. Thirdly， brand authenticity has positive effect on consumers’ purchase intentions significantly. Finally, consumer ethnocentrism plays the full mediation role on the influence of brand authenticity on the consumer’s purchase intention. The corporation force moderates the relationship between brand authenticity and consumer ethnocentrism negatively. This paper clarifies the domestic consumers’ psychological mechanism of interpretation and feedback to brand authenticity perception and behavior towards domestic brands during internationalization, thereby helping provide enlightenment on brand strategies for the brands in the domestic market．