The unstable-resonator spatially enhanced detection (USED) coherent anti-stokes Raman spectroscopy (CARS) measurements of temperature and N_(2) concentration in the combustion of solid propellant at atmosphere pressure are reported. The USED CARS measurement system has a high spatial solution of ~ 0.1 mm in diameter and 3 mm in length, and permits instantaneous measurement at 10-Hz rate. The single-pulse N_(2) Q-branch CARS spectra have been obtained from the propellant combustion. The temperatures and N_(2) concentrations of the propellant flame at different height have been achieved by fitting the experimental data to theoretical spectra. The results indicate that the temperature is up to ~ 2500 K with N_(2) concentration in a range from 10% to 26%.