The invention relates to a variable and controllable cavitator, which comprises a large jar body and a small jar body, wherein the small jar body is located on the right side of the large jar body, and is communicated to the large jar body, the left port of the large jar body is covered with a large jar end cover, the right port of the small jar body is covered with a right end cover, the right end of the small jar body is connected to a fluid inlet, the right end of the large jar body is connected to a fluid outlet, the left port of the small jar body is provided with a flow intercepting cone, a flow passing throat port is arranged along the axis of the flow intercepting cone, a sliding plate capable of axially sliding along the inner wall of the large jar body is arranged on the middle section of the inner cavity of the large jar body, the left side of the large jar end cover is connected to an end cover box, a piston is arranged in the center hole of the large jar end cover, is driven by a screw rod sleeve, and is connected to the sliding plate through a connecting cylinder, a screw rod shaft is screwed in the screw rod sleeve, a jet cone is fixed on the right end head of the screw rod shaft, and is inserted into the flow passing throat port of the flow intercepting cone, and a fixed pore plate is arranged on the right end of the flow intercepting cone, and is provided withan adjustable center hole and peripheral holes. According to the present invention, the cavitator can achieve multiple cavitation modes, and has characteristics of high raw material adaptability and good cavitation effect.