The distribution of working gas spectral lines and cathode material in the optical radiation of arc discharge plasma with a hollow cathode is investigated. The dependences of the spectral line intensities Xe I-4807.02 Å, Xe II-4844.33 Å and La II-3949.1 Å on the parameters of the external arc column plasma, cathode wall temperature and discharge characteristics are defined. With the help of the probe and spectroscopic measurements the parameters of the cathode internal plasma are determined. The physical processes occurring in the arc with a hollow cathode on the grounds of the experimental data are discussed.