Eight new laser lines of the chlorine ions in the visible region are reported in this paper and their wavelengths are 441.48, 459.62, 460.18, 477.11, 477.89, 509.93, 517.59 and 535.61 nm respectively. The experimental results show that when an appropriote quantity of argon gas is mixed into the lasing medium of hydrogen chloride, the intensities of laser lines increase properly and more new lines can be observed. Some phenomena in our experiments are qualitatively explained as well.