As a power supply method with high spatial freedom, megahertz (MHz) wireless power transfer (WPT) has great potential in particular application fields. The role and importance of WPT are described from the perspective of interdisciplinary. This article starts with WPT systems’ performance at different frequencies, emphasizes the basic composition and working principle of MHz systems, and focuses on a comprehensive review of recent years on inverters, rectification, impedance compression, dynamic impedance matching, coupling structure design, and multiload model establishment. Meanwhile, different technologies are summarized, compared, and classified. Current challenges and future development trends are discussed.