The VUV emission spectra of HT-6B tokamak from 43.0 to 130.0 nm are photographed. The spectrograph used is model 247 grating incidence spectrograph. More than one hundred spectral lines have been identified. Besides Laman series of hydrogen which is the working gas, almost all lines are those of light impurities, i. e. oxygen, carbon and nitrogen. The spectral lines of sulfur are found firstly. The reason of exist of sulfur is explained.