The invention discloses a two-stage cavitation bubble generator, comprising: a first cavitation section, which includes a first jet chamber, a compression channel, an air cavity, and a mixing channel; the first jet chamber, a compression channel, an air chamber, The mixing channel communicates in sequence along the fluid flow direction; the second cavitation section, which includes a second jet chamber with an open end, an outlet channel for outputting fluid, and a central body; the open end of the second jet chamber is connected to the fluid in the first cavitation section The output end is connected, and the other end of the second jet chamber communicates with the outlet channel; the wall of the second jet chamber is provided with a low-pressure fluid inlet communicating with it; the center body is arranged in the middle of the second jet chamber and is fixedly connected with it, and the center body The radial center is provided with a center body channel for mixing fluid and gas. The cavitation bubble generator has high cavitation efficiency, and a single generator has a wide range of cavitation effects, which can be effectively used in the dissociation process of high-sulfur slag, improve the separation effect of slag-sulfur, and provide a good solution for subsequent flotation sulfur extraction. Base.