Abstract: In kinescope electron gun design there are three chief factors which affect the final electron beam spot size. Thes are the magnification factor, the spherical aberration and the space charge effect. In this paper the interrelation between these factors and the resolution is discussed.In order to reduce beam crossover and divergence angle, some methods which make nse of reducing the aperture diameter of G1 and increasing the spacing between G1 and G2 are proposed. By adjusting the position of the electron gun in the kinescope i.e.increasing the distance between the gun and the yoke, the deflection defocusing which is caused by scattering magnetic field of deflection yoke is reduced. Therefore, focnsing performance of kinescope is improved effectively and its edge resolution is increased. Test data show that the above methods are excellent, the increment of edge resolution is better than 50 lines.