Abstract: Based on the CORS network of the United States in 2018, data from four short baselines with length of about 11 km and different elevation difference between stations are selected for the experiment. In the case of estimating tropospheric delay, the baselines are solved by setting different elevation mask angles, and the results are compared by standardized root mean square error, baseline U-direction repeatability and baseline difference. The analysis results show that for the short baseline with elevation difference more than 100 m, the selection of elevation mask angle is not the main factor affecting the accuracy of elevation direction calculation; and the geodetic height of the station has a certain impact on the accuracy of short baseline elevation direction calculation.