A constant pressure fiber attenuated total reflection (ATR) probe which can be used in infrared spectrum analysis and in situ nondestructive testing is developed. Combined with constant pressure inhabiting device, the probe contacts with the sample under constant positive pressure based on ATR technique. It can significantly improve test repeatability of sample absorption spectra, and the multiple measurement error is less than 5%. The probe is used to analyze the stabilizer mass fraction in nitrate ester plasticized polyether (NEPE) propellant. The measurement results are in agreement with previous reports, and it can greatly improve the measurement convenience. The developed probe can be widely used in the occasions where the material has to be carried on nondestructive test repeatedly.