The invention discloses a carrier signal testing device and a testing method, the carrier signal testing device comprises a signal noise adjustor, and a carrier transmitter, a programmable attenuator,a noise simulator, a carrier receiver and a message comparator orderly connected in series; the signal noise adjustor generates a signal noise message which comprises a data message, an attenuation signal and a noise signal; the carrier transmitter generates a carrier signal according to the data message and transmits the carrier signal; the programmable attenuator adjusts strength of the carriersignal according to the attenuation signal; the noise simulator adds an interference signal to the carrier signal according to the noise signal; the carrier receiver receives the carrier signal and demodulates the data message; and the message comparator generates a comparison result according to the data message and the demodulated data message, and feeds back the comparison result to the signalnoise adjustor. The carrier signal testing device has the advantages of simple structure, clear detection result, random and non-single detection content, closed-loop cycling detection process, gooddetection effect, high efficiency, very high practicability and wide applicability.