In order to acquire characteristic of the output spectrum in nitrogen diluted combustor driven continuous wave deuterium fluoride laser, the spectrum analysis was accomplished basd on Z-model unstable optical resonator, which used Fourier infrared spectrum analyzer measuing scatter of the reflector mirror in out optical path. The results show that the output lines of nitrogen diluted DF laser transfer to long wavelength, and 3P10～3P13 lines with wavelength larger than 4.0 μm are brought out efficiently. Also, the transition lines of each vibrational energy level take on higher rotational quantum number. The output spectra of DF laser compete intensely existing in self and different band, and cascade effect appears among them. The distribution of DF laser output spectra can be regulated partly by adjusting the combustor oxidant excess index. It satisfies pneumatic performance with excess second fuel, and the distribution or output spectra is affected faintly with the appropriate second fuel ratio range. The results have a reference to research and application of the combustion driven continuous wave DF laser.