The invention discloses a rural power grid remote detection system based on a multi-channel power frequency communication technology. The rural power grid remote detection system comprises a plurality of concentrators located in a transformer substation and a plurality of rural grid detection terminals located at a low-voltage side of a distribution transformer; each concentrator comprises an uplink demodulation unit, a downlink modulation unit and an industrial control computer which are used for power frequency communication; and each rural grid detection terminal comprises a sensor module, a power frequency communication module and a comprehensive management module. The invention further discloses a rural power grid remote detection method based on the multi-channel power frequency communication technology. The synchronous rural power grid remote detection method implemented in the rural grid detection terminals and/or the concentrators comprises the steps of: determining a modulation time domain of each path of power frequency communication signal by adopting a matched filtering method; and performing power frequency communication denoising by adopting a self-adaptive interference cancellation technology. The rural power grid remote detection system and the rural power grid remote detection method based on the multi-channel power frequency communication technology disclosed by the invention can adapt to the regional conditions and channel environment of the rural grid, and create favorable conditions for the rural grid transformation.