Abstract: This paper discusses the inception and growth of cavity in cavitating flow of cryogenic fluid induced by orifice throttling, and presents results of the numerical simulation by combining the full cavitation model and the RNG turbulence model. The vapor fraction and the pressure distribution in cavitation region are examined. The computation results indicate that the cavitation inception spot appears in the wall of an orifice sharp corner due to its lowest pressure in the whole passage. And then, the bubble cavitations, cloud cavitations and super cavitations consecutively occur with a gradual enhancement of cavitations of cryogenic fluid by modulating throttling flow. Moreover, the vapor fraction and the pressure distribution in the three stages of cavitations are studied, and the gaseous compositions in the three stages of cavitations are examined. The paper gives a criterion of regime transition for the three stages of cavitations, and verifies the critical cavitations, which provides a foundation for further researches.