A processing method of an adaptation layer of an integrated access and backhaul node and an adaptation layer are provided. The method includes: mapping, by the adaptation layer of the integrated access and backhaul node, a received first data packet to a first bearer or channel between the integrated access and backhaul node and a first node; transmitting, by the adaptation layer of the integrated access and backhaul node, the first data packet to the first node; wherein the first node is a downstream integrated access and backhaul node relative to the integrated access and backhaul node and/or a UE accessing the integrated access and backhaul node, or the first node is an upstream integrated access and backhaul node relative to the integrated access and backhaul node or a donor node of the integrated access and backhaul node.