Abstract: Based on the introduction on circuit of main pulse and pre-pulse, the scheme about the trigger delay between pre-pulse and main pulse is introduced, and the experimental results about the adjustment of main pulse and pre-pulse are given. After the improvement on the device of capillary discharge soft X-ray laser, the original pre-pulse with over-high current is reduced and a new pre-pulse about tens of amperes is produced by pre-pulse generator. The adjusting results show that the current of pre-pulse is 20A, the first peak current of the main pulse is 40.1kA with 26.6ns risetime and 38ns duration. And the delay time between pre-pulse and main pulse is adjustable from 3μs to 50μs. These parameters can meet the need of soft X-ray laser generation.