Abstract: Based on the way how to form supercavity, a series ofprojectile experiments and moderate-speed tunnel experiments were carriedout to study the formation and development of the natural and ventilatedsupercavities in this paper. The processes of forming supercavities were recordedand discussed. The influence of cavitator parameters on the critical cavitationnumber and critical ventilation coefficient was analyzed. Qualitativefeatures of the supercavity size change were obtained. It is shown that thecavitator diameter and coutour have a similar influence on thenatural and ventilated supercavity sizes. Supercavity size increases withcavitator diameter and the formation of supercavity for a bluntcavitator is easier than for a cone cavitator under the same conditions.A cavitator of relatively small diameter might not be able to form aventilated supercavity, mainly because the natural cavitation number isnot small enough. Furthermore, the research shows that the cavitator diameter has animportant effect on the fineness ratio of the ventilated supercavity, whichis not the same as the natural supercavity. Finally, the perspective futureresearch on cavitators is discussed.