The invention provides a double-rotor two-stage enthalpy-increase compressor, including: an inhalation pipe, a liquid separator, a housing inhalation pipe, a lower flange, a lower cover plate, a compressor housing, an enthalpy-increase pipe, an enthalpy-increase capillary, a low pressure cylinder, a lower roller, an intermediate plate, a high pressure cylinder, an upper roller, an upper flange, a crankshaft, a motor rotor, a motor stator, an exhaust pipe and a low pressure cylinder. The low pressure cylinder and the lower roller therein are disposed on the lower flange; the lower cover plate is disposed at the bottom of the lower flange; the enthalpy-increase pipe is disposed on the lateral of the lower flange; and a silencer expansion chamber is disposed in the lower flange. The invention also provides an air conditioner and a heat pump water heater.