A method and related apparatuses for Contention Based (CB) uplink transmission are provided by the present invention. And the method includes: configuring CB user group numbers and configuring a same CB Radio Network Temporary Identifier (CB-RNTI) for multiple CB user groups; for the multiple CB user groups having the same CB-RNTI, configuring a same CB Grant. With the present invention, it is not necessary to send a CB Grant for every CB user group, so that the resource overhead for CB Grant transmission is reduced, and thus the occurring probability of scheduling blocking is reduced.