Cross-border data flow brings new growth and opportunities for the development of digital economy, but disordered cross-border data flow may damage national security, public interests, enterprise interests, and data sovereignty. At present, the unified rules for global regulation of cross-border data flow have not yet been formed. The existing rules are mainly led by developed countries like Europe and the United States. There is huge room for improvement in the international legal protection of cross-border transmission of personal information. This paper introduces the privacy protection mechanism of personal information data under the digital trade environment in China, that is, the privacy protection framework under the background of big data, cloud computing, and the cloud service selection method of data life cycle privacy protection. At the same time, we combined with many problems existing in the cross-border transmission of personal privacy information in China and compared with foreign advanced experience, and this paper puts forward China’s response path to clarify the obligations of data controllers and exporters, improve the responsibilities of regulators, improve the legislation of cross-border data flow, and improve the operability of the law; we vigorously carry out international cooperation and actively participate in the formulation of international rules, so as to further protect the rights and interests of personal privacy information protection.