Provided are a packet transmission method and device and a computer storage medium. The method includes: a FlexE shim receives an Ethernet packet forwarded by a switching module and sent by a processor, the FlexE shim being located between a PHY layer and a MAC layer, and the switching module including a data link layer and a network layer; and the FlexE shim converts the Ethernet packet into a PPP packet, codes the PPP packet, and then inserts the PPP packet into a FlexE overhead of a target FlexE port for transmission.