Ultrasonic wave creates an effect as internal explosion in fat layer of body. The expansion and compression of wave produce a lot of tiny holes inside the liquid, and the gas and vapor exists in the tiny holes. In the compression phase, ultrasonic wave imposes a positive pressure on liquid molecule, whereas a negative pressure is created through the expansion cycle. There is a cohesion effect inside the liquid or biological tissues. Inside the low-density lipocyte, the cohesive effects are comparatively weak. A negative pressure, which is relative low, can create tissue gaps easily. It is called as Cavitations in physics. The explosion effects inside and outside the cells will increase the molecular movements, so as to achieve an high energy state, then lead to the lipocyte cracking, and achieve the goal of slimming.