Abstract: In order to suppress effect of optical fringes on detection accuracy, based on the characteristics of optical fringes, a method was proposed to compensate the optical fringes produced by parallel surfaces. Theory analysis and experimental verification were performed in a carbon dioxide detection system. The process and compensation results were shown. The results show that even in the case of optical fringe drift, the method can effectively compensate the optical fringes. The fitting correlation between the measured gas absorption signal and the standard gas absorption signal is increased from 0.8298 to 0.9934. The standard deviation of the measurement value of volume fraction was reduced from 1260×10^-6 to 48.5×10^-6. The method is very suitable for compensating the optical fringes caused by detector windows, gas pool windows, and other optical elements integrated into the system. It has great application value in the field of tunable diode laser absorption spectroscopy.