Abstract: The Jinping Underground laboratory for Nuclear Astrophysics(JUNA) group is planing to take the advantage of the ultra-low background of China Jinping Underground Laboartory(CJPL) and a high current accelerator based on an 2.45 GHz ECR ion source to study some key reactions of the nuclear astrophysics at their stellar energies for the first time. The experiments in JUNA project need proton, He⁺ and He²⁺ beams with intensities of 10, 10 and 2 emA, respectively. The most challenging part of the design and fabrication of ECR ion source is the production of the He²⁺ beam with intensities at the level of milliamperes. The traditional particle identification method based on magnetic rigidity is difficult to distinguish the He²⁺ and H⁺ ions because of their similar mass-to-charge ratios. Therefore, a novel method using nuclear reactions has been developed in this work for the identification of A/q=2 beam species from the ion source. The result shows that the 2.45 GHz ECR ion source can't produce the He²⁺ beam with a intensity of milliampere. Based on this result, a 14.5 GHz ECR ion source has been developed which has produced 2 emA He²⁺ beam successfully.