The spectra of argon excited by alpha-particIes with about 5.5 MeV emitted from 238Pu have been measured by using a home made single-photon counting system consisting of a monochrometer, photomultiplier tube (PMT) and single channel ect.. Twenty-nine spectral lines between 300-600 nm are successfully identified. The variation of the intensity of some lines with argon pressure is given. The lines of 472.8 nm, 487.9 nm ect. would be possible nuclear pumped laser lines in consideration of a simplified population analysis.