A new pre-burning circuit designed for 4×65 F pulsed xenon lamas is ptesented in this paper. Since a half- bridge switching mode converter consisting of saturated transformer is employed, the step-up transformer, current-limiting resistor and trigger circuit which were involved in the previous circuit are no longer used in the new circuit. The volume and weight of the new circuit are obviously reduced while the efficiency is enhanced. The practical operation shows that this circuit is stable and reliable.