Abstract: Pulse shaping of KrF laser by pulse stacking was experimentally studied. Compressed pulses by stimulated Brillouin scattering, short pulses with pulse-widths of 3~5 ns were gained. Shaped pulses with pulse-widths of 10~15 ns, flat-top-widths of 5~10 ns were obtained under four laser beams stacking. Using these experimental data, pulse stacking was numerically simulated, and similar results (pulse-widths of 12.7 ns, flat-top-widths of 7.7 ns) with experiment were acquired. Ability of arbitrary pulse shaping was numerically studied, and the influence of various pulse widths on shaped pulse was discussed. When variation of pulse width was less than 5%, it had little influence on shaped pulse. The amplification of the shaped pulse was theoretically and qualitatively analyzed. The results show