In order to measure the basic plasma parameters, well understand the mechanism of microhollow cathode discharge(MHCD), the rotational structures of the N2 first positive bands (B3ΠgA3+u) were analyzed with traces of nitrogen added in argon for the measurement of the gas temperature, and the Stark broadening of Hβ lines was analyzed for the determination of the electron density. The experimenual results show that the gas temperature increases with the increasing pressure and the current and can reach 700 K in the stable glow region. The electron density is in the order of 1014-1015 cm-3. The magnitude and the changing relations can provide substantial experimental data and technical support for the wide application of MHCD.