A method for associating a user with a group, comprising: receiving, by a first communications device, a first association request from a second communications device, wherein the first association request comprises an identifier of a mission critical push to talk over, MCPTT, user and identifiers of N MCPTT groups, the first association request is used to request to associate the MCPTT user with the N MCPTT groups, and N is an integer greater than or equal to 1; associating, by the first communications device, the MCPTT user with M MCPTT groups of the N MCPTT groups according to association subscription information of the MCPTT user, wherein the association subscription information of the MCPTT user is used to indicate an MCPTT group that the MCPTT user can be associated with; and sending, by the first communications device, a first association response to the second communications device, wherein the first association response is used to indicate that the MCPTT user is successfully associated with the M MCPTT groups of the N MCPTT groups, 1≤M≤N, and M is an integer; wherein the first communications device is a first MCPTT server configured to manage the N MCPTT groups, and the second communications device is a user equipment, UE; and characterized by the associating comprising: determining, by the first communications device according to a first association subscription information of the MCPTT user which is obtained according to group information of the N MCPTT groups, to associate the MCPTT user with R MCPTT groups of the N MCPTT groups, wherein 1≤R≤N, and R is an integer; sending, by the first communications device, a second association request to a second MCPTT server configured to manage the MCPTT user, wherein the second association request comprises the identifier of the MCPTT user and identifiers of the R MCPTT groups, to request the second MCPTT server to determine, according to the second association request and a second association subscription information of the MCPTT user which is obtained according to subscription data of the MCPTT user, to associate the MCPTT user with the M MCPTT groups of the R MCPTT groups, wherein 1≤M≤R; receiving, by the first communications device, a second association response sent by the second MCPTT server, wherein the second association response is used to instruct the first communications device to associate the MCPTT user with the M MCPTT groups of the R MCPTT groups; and associating, by the first communications device, the MCPTT user with the M MCPTT groups according to the second association response. receiving, by a first communications device, a first association request from a second communications device, wherein the first association request comprises an identifier of a mission critical push to talk over, MCPTT, user and identifiers of N MCPTT groups, the first association request is used to request to associate the MCPTT user with the N MCPTT groups, and N is an integer greater than or equal to 1; associating, by the first communications device, the MCPTT user with M MCPTT groups of the N MCPTT groups according to association subscription information of the MCPTT user, wherein the association subscription information of the MCPTT user is used to indicate an MCPTT group that the MCPTT user can be associated with; and sending, by the first communications device, a first association response to the second communications device, wherein the first association response is used to indicate that the MCPTT user is successfully associated with the M MCPTT groups of the N MCPTT groups, 1≤M≤N, and M is an integer; wherein the first communications device is a first MCPTT server configured to manage the N MCPTT groups, and the second communications device is a user equipment, UE; and characterized by the associating comprising: determining, by the first communications device according to a first association subscription information of the MCPTT user which is obtained according to group information of the N MCPTT groups, to associate the MCPTT user with R MCPTT groups of the N MCPTT groups, wherein 1≤R≤N, and R is an integer; sending, by the first communications device, a second association request to a second MCPTT server configured to manage the MCPTT user, wherein the second association request comprises the identifier of the MCPTT user and identifiers of the R MCPTT groups, to request the second MCPTT server to determine, according to the second association request and a second association subscription information of the MCPTT user which is obtained according to subscription data of the MCPTT user, to associate the MCPTT user with the M MCPTT groups of the R MCPTT groups, wherein 1≤M≤R; receiving, by the first communications device, a second association response sent by the second MCPTT server, wherein the second association response is used to instruct the first communications device to associate the MCPTT user with the M MCPTT groups of the R MCPTT groups; and associating, by the first communications device, the MCPTT user with the M MCPTT groups according to the second association response.