Abstract: Up to now the way of measuring solid precipitation tempera-tore is by the laser. 'This way is only fit to the light and transpar-ence oil, but can not measure the black oil because the light is not able to penetrate it. The solid precipitation determinedul-trasonic was studied in the paper, using diesel oiI as the solvent,measuring its separating temperature in the diesel oil with the
different consistency after the paraffine being heated and dis-solved in the diesel oil. Discovering by the experiment that was the paraffine's precipitation temperature increases with its consistency increasing, on the other hand, the velocity of ultrasonic spreading in the oil increased with the paraffine's consistency increasing and decreased with the temperature increasing. The experiment also discovered that the temperature decreased very slowly and even didnt decline because that the wax precipitation was a exothermic process, and the length of horizontal beeline was appeared on -the curve of ultrasonic spreading time.

Key words: ultrasonic wave, paraffin wax, solid phase deposition