A method for establishing a resource access authorization in M2M communication is provided. When an entity including a terminal, a gateway and an end user as client in a first M2M service provider domain attempts to access resource located in terminal or gateway in second M2M service provider domain, the method includes receiving client credential allocated from M2M Authentication Server (MAS1) in first M2M service provider domain by performing client registration to Network Service Capabilities Layer (NSCL1) in first M2M service provider domain by client, requesting an authorization to access resource to resource owner through NSCL (NSCL2) in second M2M service provider domain based on information about Universal Resource Identifier (URI) of resource by client, verifying client through MAS1 by the resource owner, authorizing client to access the resource by the resource owner, and issuing access token to the client by MAS (MAS2) in second M2M service provider domain.