In this paper the self-sharpening effect of electron beam landing on the target in a vidicon and its influence on resolution of electron beam have been digitally analyzed with computer. The mathematical-physical models applied are as follows: The distribution of current density in electron beam is Gaussian; the energy distribution of electrons in beam is Maxwellian; and the signal-readout model is capacitor discharge model. When the model of cross section of beam is one-dimensional, the self-sharpening effect of beam in 1¼ and 2/3plumbicon, 1 Sb2S3 vidicon and 1staticon are computed. Also their influences on AR (amplitude response) of electron beam have been computed. The influences of beam current, signal current, equivalent temperature of beam, target capacitor and velocity of scanning on the self-sharpening effect have been analyzed. when the model of cross section of beam is two-dimensional, the self-sharpening effect of beam in1¼plumbicon, as an example, is given.