A spectroscopic measuring system was described and developed to analyze the time-varying optical spectra of electrical contacts. A simulaton system of contact life, a monochromator, a photomultiplier tube (CR114) and a four channel digital storage oscillograph are used as optical detectors, so that the precise and quick measurements can be made for the spectrums with tim. At the same time, arc voltage waveform is measured for the breaking arc at the source voltage E of 24 V and the closed contact current I of 18 A. It is shown that this system can be applied to analyse the electric arc light and voltage for spectrums, and the dynamic characteristic of the breaking arc on Ag and Ag/MeO electric contacts.