Abstract: A new xenon flash lamp triggering method is discussed based on trigger and pre-ionization integrally. The pre-ionized lamp is lighted by high voltage trigger circuit, and the current is kept by pulse forming network for 150 s. A trigger power supply is designed for the xenon lamp with a length of 160 mm, a diameter of 9 mm and a gap of 70 mm. The pre-ionized voltage amplitude is 300-900 V, pulse width is 150 s20 s, raising-time is less than 90 s, trigger delay time is less than 90 s, and jitter time is less than 2 s. Experimental results has testified the feasibility of the design theory and method.