For obtaining simple mono-pulse laser of nanosecond burst-length and high peak power with available equipments in order to satisfy time-resolved demands in something to do with military application and in interferometric research of high temperature plasma, the trigged gap of KDP Pockels cell for chopping Q-beam itself was optimized by using certain patent technique, the dilemmas of dual reliability as well as synchronism of whole system were overcome in both static electric-separating of the gap enduring at full-wave voltage (Vλ) of 19 kV and easily puncturing of the insulating film between gap′s electrodes by the low front of Q-beam self-triggering, the high-speed triggering and the chopping near the peak of Q-beam were guaranteed, and a mono-pulse laser of 1.7 ns burst-length with 4 mJ pulse energy cut apart from Q-beam of a 30 ns/80 mJ traditional ruby laser was realized. Experimental investigation and theoretical analysis indicate, the optimized pre-processing distorted the distribution of the electric field between gap′s electrodes, strengthened the effect of the Q-beam′s triggering, and ensured the chopped laser pulse with short duration and high power.