The utility model discloses an ejector which comprises a receiving section, a throat section, a mixing section and a pressure reduction section. The receiving section is provided with a first inlet and a second inlet. One end of the throat section is communicated with the receiving section and located at the downstream of the second inlet. The mixing section is located between the throat section and the pressure reduction section. The pressure reduction section is located at the downstream of the throat section. The other end of the pressure reduction section is provided with a first outlet. The pressure reduction section comprises a plurality of annular parts which are communicated. Each annular part has at least two flowing passages. Each flowing passage comprises a third inlet, a second outlet and a passage extending between the third inlet and the second outlet. The plurality of annular parts a fixed in a stacked manner along the flowing direction of fluid. A rotation inclination angle exists between the third inlet of one of the annular parts and the corresponding flowing inlet of the previous annular part, the rotation inclination angles from the first annular part to the last annular part gradually increase, and the rotation inclination angle of the third inlet, relative to the corresponding third inlet of the first annular part, of the last annular part is 20-60 degrees.