This chapter deals with the PEMF devices that have been widely used clinically to treat nonunion fracture, accelerate bone fracture recovery, and slow down osteoporosis. It is an extension of Chapters 6 and 7 to the case of bone remodeling under PEMF. The theoretical and numerical results presented in Wang and Qin [1] are described. Typically, a computational method of system biology is used for analyzing bone remodeling under PEMF at the cellular level, based on experimental findings and recent mathematical advances.