Abstract: In order to study the effect of the laser electromagnetic field on the electron in vacuum，based on the Lorentz equation，the motion track of electrons was simulated，and the electrons were accelerated in the laser electromagnetic field. Then the radiant energy spectrum was obtained according to the flux density generated by the motive electron. Finally the radiant characteristics of the relativistic electrons were analyzed. It is shown that Gaussian laser electromagnetic field has beneficial effect on vacuum electron acceleration，and its maximum speed along the optical axis is up to 0.9c.