The present invention relates to a wireless communication system. More specifically, the present invention relates to a method and a device for processing received RLC PDUs for D2D communication system, the method comprising: receiving a first RLC (Radio Link Control) PDU (Protocol Data Unit) for a RLC entity from a peer UE; establishing the RLC entity to process the first RLC PDU; setting a plurality of state variables for the RLC entity to a RLC sequence number (SN) of the first RLC PDU for the RLC entity; and processing the first RLC PDU using the plurality of state variables for the RLC entity set to the RLC SN of the first RLC PDU for the RLC entity.