Aiming at the scale problem in heat-transfer equipments, experimental investigation on antiscale and scale removal by ultrasonic cavitation is performed. By means of microscopic magnifying photography system, the sedimentary phenomenon can be observed. The experimental research reveals the influencing rule of acoustic intensity, cavitational distance, liquid temperature and solution concentration. The experimental results indicate that liquid temperature has different effects on antiscale and scale removal. Different experimental liquids are used for antiscale and scale removal experiments. The results show that every liquid has a respective cavitational active temperature. When ultrasonic is used for antiscale, the smaller acoustic intensity is, the better effect is. But, when ultrasonic is used for scale removal, acoustic intensity has a reverse influence. In addition, biggish solution concentration is propitious to antiscale for long-time running. Distance of test sample to ultrasonic transducer also has certain influence on antiscale and scale removal. The smaller the distance to ultrasonic transducer is, the better effects antiscale and scale removal have.