This paper studies the theory of radio wave atmospheric refraction, analyses the propagation error factors, explains the difference of signal propagation path between the regional navigation system and GNSS satellite navigation, discusses the impact of tropospheric delay on the measurement accuracy of regional navigation signals, and a tropospheric delay error correction model is designed to fit the application requirements of regional navigation systems. Through simulation research, the feasibility of tropospheric delay error correction model designed for regional navigation system is verified, and the error correction capability is given at long distance with low elevation angle and close range with high elevation angle.