Abstract: In this paper,we computed and analyzed behavior of FEL gener-ated for infinite, finite and short micropulse of electron beam by 3-D HGFEL code that we developed recently. Results obtained for the first two cases coincide with not only those obtained by 3-D OSIFEL code, but CPU time spent by 3-D HGFEL code is much less than that by 3-D OSIFEL code. We preliminarily computed and analyzed the evolution of Beijing FEL optical pulses for the last case.