A capillary discharge setup, consisting of a Marx generator system, main switch, Blumlein transmission line and pre-pulse circuit, has been developed . This device is designed to excite electron-collision pumping scheme XUV laser in Ne-like Ar at 46.9 nm. The ablation characteristics of the discharged capillary are experimentally investigated by measuring VUV emission from the capillary discharged. The ablation of capillary wall for polythene and alumina material is studied at inherent pre-pulse (7 kA) of the Blumlein transition line (BIL) and at pre-pulse of 20～30 A respectively under the same main current of 30 kA having a rising time of 30 ns. The reason of the plentiful ablation is that there exist high electric fields for inherent pre-pulse, which cause an inhomogenous channel spark near the wall. The experiment results indicate that the inherent pre-pulse of BTL on grounding inductance is too large to create uniform plasma columns. In the case of 20 A-pre-pulse the background emission decreased remarkably and the radiations is discriminable. In the experiments, only when the pre-pulse is less than 100 A, for alumina capillary, can the ablation be greatly reduced.