Abstract: Experimental investigation of aqueous solution of the gelatin has been made by using ultrasound with frequency 11.4 MHz. The relation between concentration and ultrasound absorption shows that ultrasound absorption does not reach its saturated value until the weight concentration of the solution c=8.5%.
When the concentration of the solution is more than 1.5%, it can transform into gel under the room temperature and the ultrasound absorption does not change in the whole transformation process. When temperature of solution is decreased to the vicinity of the gelling point, the viscosity of solution increases gradually with time, thus making the classical value of sound absorption larger that the experimental one by seevral orders. But when the temperature of solution is appropriately higher than the gelling point, the classical value of sound absorption may be smaller than the experimental one but with the same order.
The temperature at which the maximum ultrasound velocity occurs in the concentrated （c=6.4%） solution is not much different from that in pure water. All the phenomena observed has been discussed.