The invention discloses an HSR/PRP network sampling synchronization method based on data forwarding time-delay measurement, and the method comprises the steps: giving a timestamp to an SV message at the input and output ports of a basic communication unit RedBox of an HSR/PRP network; carrying out the measurement and accumulation of transmission time delay of the SV message on the RedBox, and writing the accumulated time delay into a message time domain, thereby achieving the precise measurement of the accumulated transmission time of the SV message among HSR rings and between the HSR rings and a PRP network; enabling an SV message receiving device (such as a protection device, a measurement and control device) to take a local clock as the reference, and deducing the transmitting moment of an SV message of a merging unit according to a value in a time domain of the received message, thereby achieving the synchronization of sampling data. The method can effectively solve a problem that the sampling synchronization of the HSR/PRP network depends on a public clock signal.