An introduction is made to the principles and measuring method of the ultrasonic snow depth sensor. Based on the snow depth data observed by the two methods, ultrasonic sensor and manual observation in the Jiamusi national reference climatological station，comparison and analysis are made in different weather conditions (high wind velocity, low wind velocity, low temperature). The results show that the differences are mainly influenced by wind velocity and temperature. At high wind velocity, the ultrasonic pulses are greatly affected by wind speed, leading to the departure of the ultrasonic pulses from the bottom of the ultrasonic sensor; meanwhile, the speed of ultrasound pulses is also affected, and thus, the measurement results are affected. The travel time of ultrasonic pulses is affected by the temperature, so when the temperature was extremely low, the performance of ultrasonic sensors is obviously affected.