The present invention relates to a wireless communication system. More specifically, the present invention relates to a method and a device for receiving a MAC CE for contention-based PUSCH in a wireless communication system, the method comprising: configuring a CB grant and a CB-RNTI associated with the CB grant; transmitting a MAC PDU including an identifier of the UE and CB grant occupancy information using the CB grant; receiving a CB MAC CE including the CB grant occupancy information indicated by a PDCCH addressed to the CB-RNTI in response to the MAC PDU transmission; and transmitting next uplink data using the CB grant during time duration indicated by the CB grant occupancy information if the identifier of the UE is included in the CB MAC CE.