Abstract: A pulsed radio frequency hollow cathode plasma source was used to excite working gas containing methyl bromide and the plasma emission spectra were measured by HR4000 high-resolution spectrometer. Two characteristic peaks of bromine atom respectively at 635.07 nm and 700.52 nm were observed. The influence of gas pressure and concentration of methyl bromide on the intensity of the two characteristic peaks was investigated. The results show that the intensity the two characteristic peaks decreases with the increasing of gas pressure at the same concentration of methyl bromide, and increases with the increasing of the concentration under the same gas pressure. The accuracy of methyl bromide concentration measurement can be better than 1 g/m3.