Abstract: In light of the solution of electron motion equation in a magnetic field, the electron scattering in response to the incident electromagnetic wave of frequency wi includes the part whose frequency is the same as the cyclotron one besides that of frequency wi. This effect can be called the self-excitation and, except the highfrequency limit, has a considerable influence upon the cross section. In this paper, the modified cross sections of classical non-relativistic electron in the case of both a single electron and cold plasma are. given. The spectrum distribution of electron scattering is discussed, and the Thomson absorption coefficients of magnetized thermal equilibrium plasma are obtained for some typical cases. It is also pointed out that the result here can be applied for many astrophysical aspects such as the spectrum formation of X-ray pulsars.