Abstract: In this work the results of measurement are given for the velocity of ultrasonic waves in suspended monodispersed particles-the spore of lycoperdon in some solvents. The measurement is carried out at different temperatures （from 10 to 60℃） and concentrations （from 12 to 70%） by an ultrasonic interferometer of constant frequency at 1 Mhz. On the basis of the data, the behaviour of variation of ultrasound velocity in suspended matters under different conditions is investigated in detail. It is shown that, for the given suspended matter, the sound velocity square obeys the formula of additivity. The compressibility of the particles under consideration for different temperatures is calculated according to the Herzfeld’s simplified formula.