An apparatus and method for processing a packet in a multi-protocol label switching-transport profile (MPLS-TP) network are provided. In the method of processing a packet, a packet transport layer (PTL) index and a layer stack (LS) or multiple label pop (MPOP) loopback header are used, and it is possible to remove a size limitation on lookup results of a lookup table when multiple labels are stacked, and solve the problem of having to extract all labels as label keys regardless of label operations upon an incoming label map (ILM) table lookup.