Abstract: The factors which influence the Compton line in Compton scattering are very complex. Those main factors are discussed, they include： the initial velocity can enlarge the changed wavelength; the bound energy could reduce the changed wavelength; the double Compton scattering and the Compton scattering which produces two photons change the changed wavelength, and the changed wavelength is uncertain, complex and continuous. At last the authors draw a conclusion and make a prospect for the research of the theory and its applications of Compton line and profile.

Key words: Compton scattering, Compton profile, double Compton scattering, changed wavelength