Abstract: The first high intensity proton radio-frequency qaudrupole (RFQ) accelerator with four-vane structure was built in collaboration between Institute of High Energy Physics and China Institute of Atomic Energy under the support of the accelerator-driven clean nuclear energy program in the State Key Basic Research Project in China. The advanced accelerating structure can provide a periodical strong focusing to the low-energy high-current beam from an ion source, while bunching and accelerating the beam in longitudinal direction. The RFQ accelerates proton beam of 46 mA pulse current to 3.5 MeV at more than 7% duty factor. The physics design, experimental study and beam commissioning of the RFQ are introduced in this paper.