[en] The behaviours of a nitrogen plasma jet operating at pressures between 10 torr and 35 torr has been spectroscopically investigated. The relative intensity has been plotted against the pressure, plasmatron power and the plasma jet length for different pressures. The radial distributions of relative intensities for the same spectral lines against the plasma jet length have been plotted too. The measurements have been taken for two wolfram spectral lines and two heads of second positive nitrogen molecular bands. (author)