 Strongly coupled magnetic resonance, SCMR, proposed by researchers at MIT in 2007, attracted the world's attention by virtue of its mid-range, non-radiative, and high-efficiency power transfer. In this paper, current developments and research progress in the SCMR area are presented. Advantages of SCMR are analyzed by comparing it with the other wireless power transfer, WPT, technologies, and different analytic principles of SCMR are elaborated in depth and further compared. The hot research spots, including system architectures, frequency-splitting phenomena, impedance-matching and optimization designs are classified and elaborated. Finally, current research directions and development trends of SCMR are discussed. This article was authored by Shuja Wei, Jinsher Wang, and Haifeng Dai.