Physical properties of soy milk such as temperature, pH, density and absorbance alter with the change of the process parameters of the high intensity ultrasound. A research was conducted with a device of maximum output power of 100 W, a frequency of 30 kHz, probes of a diameter of 7 and 10 mm and with a device of maximum output power of 200W, a frequency of 24kHz, probe of a diameter of 14mm at the values of the amplitude (A = 20, 60 and 100 %), the time of processing (t =2, 6, 10 and 15 minutes) and the applied cycle of 0,6; 0,8 and 1.The goal of this thesis was to determine the optimal process parameters which provoke by far the biggest change of temperature, pH, density and absorbance values of soy milk using probes of the diameter of 7 mm, 10 mm and 14 mm. The volume of processed milk was 150 mL. The results were statistically analyzed with "Statistica 8" program and the influences were demonstrated by the analysis of variance (ANOVA). The importance of each process parameter on the particular physical property is represented in Post-hoc analysis (Tukey - test).