To ensure the uniformity of plasma generated by the ion source in the neutral beam system, a large-area high-current ion source with multi-drivers is designed in the neutral beam system 1 . When these drivers are simultaneously supplied with alternating current work at the same time, there may be mutual coupling and interference between themselves 2,3 due to the small distance between them (about 10 cm), which results in an asymmetric distribution of the RF magnetic field in the driver, thereby affects the normal operation of the RF ion source. In this study, a three-dimensional numerical simulation model of the 2-drivers of the radio frequency ion source was established. The electromagnetic induction between the two drivers was simulated and analyzed via this three-dimensional model. Under different distances, the distribution of the magnetic field in the driver without input which induced by the driver with input is analyzed. This research will provide theoretical support for the distribution of CRAFT's RF negative ion source drivers.