Abstract: Snow cover monitoring is important because the accumulation and melting of snow cover is influenced by global weather and climate, as well as changes in weather and climate. GNSS multipath reflectometry (GNSS-MR) is an emerging method for snow depth detection, but its accuracy is lower than that of other methods due to the severe influence of the undulating terrain around the station. In order to weaken the influence of terrain undulation on the accuracy of the inversion results, this paper conducts a plane grid of the terrain around the station, and constrains the results of each grid to eliminate the reflected signal in the area with excessive undulation. In this paper, taking the P360 station of the Plate Boundary Observatory (PBO) network as an example, the snow depth value from the 50th year to the 100th year of 2015 is calculated and compared with the results obtained without this method. The experimental results show that the root mean square (RMSE) calculated by this method is increased by 82.89% from 12.04 cm to 2.06 cm compared with the RMSE without this method, which proves that the method can better avoid the influence of terrain and improve the inversion accuracy.