An EtherCAT packet forwarding system with distributed clocking is provided. The system comprises a master device and a plurality of slaves. The master comprises a processing port and a forward port for being respectively coupled to the at least two Ethernet ports of the master device in a redundant ring topology. The slaves comprise an internal clock indicating a current time, and a slave memory comprising a processing timestamp variable, a forwarding timestamp variable, a temporary timestamp variable and a copy-direct bit.