The spectra of helium and kryton excited by alpha-particles (~ 5. 5 MeV) emitted from 238Pu have been measured using a home- made single- photon counting system. Thirteen spectral lines of helium between 370.0~720. 0 nm are identified, five lines of them belong to HeI's spectra, the others are the vibronic spectra of helium moleculars ; and seven spectral lines of kryton between 400.0~600.0 nm are observed. The spectral intensity varied with gas pressure have been given for He and Kr, respectively. The possible atomic and molecular processes by alpha-particles impaction are discussed.