Abstract: The neutral beam injection（NBI） heating is one of the most important auxiliary heating methods on the magnetic confinement nuclear fusion devices. The high current radio frequency（RF） driven ion source with large area is the key component of the high-power NBI system. In order to generate high density plasma in large area with good uniformity, the structure of RF plasma generator with two-driver and the characteristics of plasma was simulated based on the research experience of a single-driver RF ion source. The effects of structure of plasma generator and the operation parameters on the plasma was investigated, including the distance between two RF drivers, expansion chamber depth, RF power, and source gas filling pressure. The results give the best structure for good plasma generation. It can support the design, development and optimization of multi-driven RF ion source with large area.