Ultrasonic anemometers are suitable to a variety of industries for wind measurement demand because of small start wind speed, nomoving parts, not disturbing the wind field, and high accuracy. However, ultrasound test procedures related to wind measurements have not formalized in China. Selecting the speed test points drawing on the wind cup test procedures, tests are conducted at each point at different angles in the HDF720 lowspeed wind tunnel loop. The test results indicate that ultrasonic wind sensors can be installed in a large wind tunnel for testing, at the same wind speed, the measurement results are slightly different at different angles due to the shadow effect of wind instrument sensors. Moreover, for different wind speeds, the differences are different. Combined with the above test analysis, the measurements must be corrected according to the ultrasonic sensor installation angles when using ultrasonic anemometer to measure wind speed in real time.