The invention discloses a carrier signal power detection method. The method is characterized by comprising the following steps: step one, performing filtering through a front filtering device; step two, adding mixed frequency in a filtered radio frequency signal; step three, performing intermediate frequency filtering on the radio frequency with the added mixed frequency; step four, performing logarithm amplification on the radio frequency with the mixed frequency after the IF filtering; and step five, performing signal sampling on the radio frequency through an AD converter. A hardware circuit part mainly realizes the signal power detection of different carrier frequencies to acquire high dynamic range; the identification of an effective carrier signal is mainly realized through a software function, the signal exceeding the noise level is recorded as a suspected carrier signal after measuring the actual noise level of an electric power line, and then the analysis about power fluctuation, signal duration and signal interval is performed on the suspected signals recorded in batch to obtain the judgment whether this group of signals is the carrier signals.