An overview of the security assessment mechanism for cross-border data transfers under China's Cybersecurity Law 2016, Data Security Law 2021, and Personal Information Protection Law 2021, as well as implementing measures and guidelines. The Note discusses the thresholds, specific requirements, steps, application materials and procedures for companies to conduct security assessments for cross-border data transfers. It also provides practical advice to companies with ongoing cross-border data transfers to comply with the Chinese regulatory requirements.