This paper uses the GNSS dual-frequency observation data of the BRST port and the Severn Bridge monitoring system in the United Kingdom to perform GPS-IR water level inversion in static and high dynamic environments, respectively. To explore the feasibility and accuracy of water level inversion by traditional GNSS monitoring system in static and high dynamic scenarios. The results show that the inversion accuracy of the L1 band is higher than that of the L2 band; in the static scene, the correlation coefficient between the GPS-IR water level inversion results and the tide gauge data is above 0.98; in the high dynamic scene, the retrieval accuracy of F001 station is slightly lower, using the Empirical Mode Decomposition (EMD) method to improve the algorithm, improve the accuracy of GPS-IR water level retrieval results in complex bridge environment, compared with the classical method, Root Mean Square Error is reduced by about 50%. Improve the applicability of GPS-IR technology in different water environments, the results show that GPS-IR technology has a good application prospect in water level monitoring.