Abstract: Nowdays, it is just a hotspot in the field of frozen soil how to measure the dynamic elastic mechanical indexes of the frozen soil using ultrasonic technology.This paper will mainly discuss the influence of temperature below centigrade zero and water content upon the spreading velocity of ultrasonic in the frozen soil and the dynamic elastic mechanical indexes of the frozen soil based on the measured results of ultrasonic velocity in frozen Harbin silty clay by Japanese UVM-2 ultrasonoscope.