Abstract: In order to study laser-induced breakdown spectroscopy(LIBS) and arc spectrum of laser-triggered vacuum switch(LTVS), and analyze the micro factors affecting delay jitter. By using single-pulse ns laser to bombard the target plasma located on switch cathode and the combined method of photoelectric multiplier tube and optical filters, the data of light intensity of discrete wavelengths and the fitting curve were gotten. After theoretical analysis, the results show that the increase of the pulsed laser energy could improve the strength of target LIBS, but almost don't affect the strength of arc spectrum. The increase of switch voltage can improve the intensity of arc spectrum. Arc plasma collides and excites in the strong electric field at the switch. The ingredient proportion of plasma changes with the change of voltage. Jitter is independent of voltage magnitude, motion status of free electrons and races of arc plasmas. The main affection takes place in the triggering period. Not laser energy but switch voltage plays a major role in the steepness of voltage drop. The results are useful for the further study about laser-target interaction, pulsed-arc and delay-jitter of LTVS.