Time delay eliminating method and device for PTP data packet when converted between Ethernet and E1 protocol

The invention discloses a time delay eliminating method and a device for PTP data packets when converted between the Ethernet and the E1 protocol. The method comprises the following steps: (1) when the data packets are converted from the Ethernet to the E1 protocol, for a data packet whose sending time delay does not need to be calculated, the data packet is directly sent to a cache and waits for sending; and for a data packet whose sending time delay needs to be calculated, a sending time delay delta t is calculated at first, and then the obtained sending time delay delta t is stored; and timestamps in subsequent corresponding data packets are processed according to the sending time delay delta t so as to eliminate the sending time delay; (2) when the data packets are converted from the E1 protocol to the Ethernet, for a data packet whose timestamp does not need to be processed, the data packet is directly sent to the Ethernet; and for a data packet whose timestamp needs to be processed, the timestamp is processed according to the stored sending time delay delta t so as to eliminate the sending time delay. According to the invention, the time delay generated when the PTP data packets are converted between the Ethernet and the E1 can be effectively eliminated, that is the time delay jitter of a traditional link is compressed from tens of microseconds of a traditional E1 converter to the nanosecond level, so the link jitter can be greatly reduced, and the time service accuracy can be effectively improved.