Using rough sediment a.nd tilled loess as samples, the paper compares the advantages and faults, dispersion ability and results between ultrasonic and boiling dispersion method in different power and time. The results show that the ultralsonic dispersion method use time and electric power sparingly, being more complete in dispersion than the boiling method, its dispersion effect is 1.13 to 1.23 times of the boiling one, and that the dispersion abilibty differs from time under same frequency. The conclusion suggests that the way of dispersion at 17.5krh,220V with 500mA electric current in 25 minutes ultrasonic dispersion or 700mA in 15minutes could get better results.