In this paper, we experimentally tested the opto-spectrum output and the pressure amplitude of intensive acoustic wave by HR4000CG-UV-NIR spectrometer and NI-PCB sensor, analyzed the energy transformation relationship of sound and light, and observed the influence of discharge parameters on the opto-spectrum. The experimental results indicate that the spectrum of the light is of continuous spectrum and its dominant energy is around 500 nm. The light energy output and sound energy output compete with each other. If we raise the discharge voltage and reduce the gap distance of electrode tips, the spectrum amplitude and its half peak width will increase. If we increase the gap distance, the light energy will spread to the far ultraviolet zone. And if we change the steel tip with copper tip, the spectrum energy distribution and amplitude will change.