A compressor, comprising: a low-pressure compression component (2,10) having a low-pressure chamber, configured to take in gas and compress the gas to form first compressed gas; a medium-pressure chamber; a low-pressure chamber gas discharge passageway (21,31), through which the first compressed gas from said low-pressure compression component is discharged into the medium-pressure chamber; an enthalpy-increasing component (5,6,7,8) configured to convey second compressed gas into the medium-pressure chamber, the second compressed gas and the first compressed gas being mixed to form mixed compressed gas in the medium-pressure chamber; a high-pressure compression component (12,13) including a high-pressure chamber, configured to take in the mixed compressed gas and compress the mixed compressed gas to form a third compressed gas; a medium-pressure gas passageway (32,22,111,121), through which the mixed compressed gas from the medium-pressure chamber is conveyed into the high-pressure compression component; a high-pressure chamber gas discharge passageway (122,141) through which the third compressed gas is discharged from the high-pressure compression component; characterised in that the medium-pressure gas passageway comprises a passageway section at the side toward the low-pressure chamber gas discharge passageway, and a passageway section at the side toward the high-pressure chamber gas suction passageway, wherein, a ratio between minimum cross sectional area of the passageway section at the side toward the low-pressure chamber gas discharge passageway and minimum cross sectional area of the passageway section at the side toward the high-pressure chamber gas suction passageway is ranged from 1.4 to 4. a low-pressure compression component (2,10) having a low-pressure chamber, configured to take in gas and compress the gas to form first compressed gas; a medium-pressure chamber; a low-pressure chamber gas discharge passageway (21,31), through which the first compressed gas from said low-pressure compression component is discharged into the medium-pressure chamber; an enthalpy-increasing component (5,6,7,8) configured to convey second compressed gas into the medium-pressure chamber, the second compressed gas and the first compressed gas being mixed to form mixed compressed gas in the medium-pressure chamber; a high-pressure compression component (12,13) including a high-pressure chamber, configured to take in the mixed compressed gas and compress the mixed compressed gas to form a third compressed gas; a medium-pressure gas passageway (32,22,111,121), through which the mixed compressed gas from the medium-pressure chamber is conveyed into the high-pressure compression component; a high-pressure chamber gas discharge passageway (122,141) through which the third compressed gas is discharged from the high-pressure compression component; characterised in that the medium-pressure gas passageway comprises a passageway section at the side toward the low-pressure chamber gas discharge passageway, and a passageway section at the side toward the high-pressure chamber gas suction passageway, wherein, a ratio between minimum cross sectional area of the passageway section at the side toward the low-pressure chamber gas discharge passageway and minimum cross sectional area of the passageway section at the side toward the high-pressure chamber gas suction passageway is ranged from 1.4 to 4.