The invention discloses a cubic satellite measurement and control responder and a coherent signal forwarding method thereof, wherein the method comprises the following steps of performing direct sampling on the radio frequency of a received signal, FPGA digital processing, and digital-to-analogue conversion, wherein the output transmitted signal is coherent with the received signal; the respondercomprises a VHF frequency band antenna, a first VHF band-pass filter, a radio frequency amplifier, a second VHF band-pass filter, a high-speed ADC, an FPGA, a high-speed DAC, a UHF band-pass filter and a temperature compensation crystal oscillator TCXO; the problem that a traditional middle-large-sized satellite responder is large in power consumption and unstable in performance is solved; and a relative distance and speed measuring method for the satellite and the ground station is provided for the microsatellite. According to the responder and the method in the invention, the frequency spectrum near-end noise of the forwarded signal is low, the spectrum purity is high, and the speed measurement accuracy is only related to the reference frequency stability and the forwarding noise of theground station, so the speed measuring precision is high; in addition, a full-digitalization mode processing is adopted after radio frequency sampling is carried out, so that the temperature stabilityis higher than that of an analog circuit.