The present invention discloses a GNSS-R earth surface survey device and method. The method comprises: disposing a GNSS signal-receiving antenna capable of receiving signals at frequencies corresponding to different GNSS systems, and at the same time, acquiring, during an intermediate frequency extraction stage and via independent channels, direct signals and reflected signals of respective different frequencies, so as to obtain a digital intermediate frequency signal; selecting, based on a user setting or a signal strength, a GNSS system to be used to process data; and obtaining, via analyzing a Doppler shift and a time delay of the digital intermediate frequency signal, a difference of the GNSS reflected signal with respect to the GNSS direct signal, thereby obtaining earth surface data via backward induction on the basis of the same. In this way, the present invention enables compatibility with different GNSS system signals at the same time for earth surface survey.
