Provided are a time synchronization method and device, and a storage medium. The method includes that: a synchronized block matching a preset code pattern in a data stream is searched at a SERDES parallel interface; the position of the bit of the synchronized block in the SERDES parallel interface is determined as a first position; a time point when the synchronized block passes through the SERDES parallel interface is determined as a first time point; the synchronized block and a PTP packet in the data stream are searched at an interface between PHY layer and MAC layer, and a distance between the synchronized block and the PTP packet is determined; and a second time point is determined according to the first position, the first time point and the distance, the second time point being the time point when the PTP packet passes through an SERDES serial interface.