The magnetic circuit method is one of the practical solutions for motor analysis because an analytical model is very simple, the calculation accuracy is relatively high, and it is easy to combine with an electric circuit, motion, and thermal dynamics. In addition, a general-purpose circuit simulator like “Simulation Program with Integrated Circuit Emphasis (SPICE)” can be used as a solver. However, when the electrical machinery has a complicated structure or flux distribution, it is difficult to express it in a simple magnetic circuit model. Hence, a more detailed model, namely, a reluctance network analysis (RNA) model, is necessary. This chapter describes the derivation method of the RNA model of a surface permanent magnet (SPM) motor as an example. Furthermore, an electric-magnetic-motion coupled analysis of the SPM motor is introduced.