The spectrum range from 300 to 600 nm is measured with low energy (V≈0.01 VBohr) highly charged Krq+ ions (q=8, 10, 13, 15, 17) impacted on Al surface. The results show that the spectral lines are induced by the impact of low-energy ions on Al surface, and that these lines belong to the sputtered atoms, ions, and the incident ions which are neutralized. The intensity of emission line increases with the projectile potential. The electron of Al can be efficiently excited to the 4s state by the higher potential energy compared with the excited state of 3d.