A communication method, comprising: generating, by a first communications device, a Media Access Control, MAC, protocol data unit, PDU, data packet, wherein the MAC PDU data packet comprises at least one first-type MAC control element, CE, each first-type MAC CE is used to carry information about at least one secondary serving cell, and the first communications device determines a location of the first-type MAC CE in the MAC PDU data packet according to a secondary serving cell corresponding to the first-type MAC CE; and sending, by the first communications device, the MAC PDU data packet to a second communications device, so that the second communications device obtains the first-type MAC CE, and determines, according to the location of the first-type MAC CE in the MAC PDU data packet, the secondary serving cell corresponding to the first-type MAC CE, to obtain information about the secondary serving cell; wherein the determining, by the first communications device, a location of the first-type MAC CE in the MAC PDU data packet according to a secondary serving cell corresponding to the first-type MAC CE comprises: determining, by the first communications device, according to the secondary serving cell corresponding to the first-type MAC CE, a location of each first-type MAC CE in MAC CEs in the MAC PDU data packet, characterised in that each first-type MAC CE is used to carry information about N secondary serving cells, and the determining, by the first communications device, a location of the first-type MAC CE in the MAC PDU data packet according to a secondary serving cell corresponding to the first-type MAC CE comprises: if a first MAC CE in the at least one first-type MAC CE carries information about secondary serving cells whose corresponding cell indexes are (X-1)*N+1 to (X-1)*N+N, determining that the first MAC CE is the X th MAC CE in the MAC PDU data packet. generating, by a first communications device, a Media Access Control, MAC, protocol data unit, PDU, data packet, wherein the MAC PDU data packet comprises at least one first-type MAC control element, CE, each first-type MAC CE is used to carry information about at least one secondary serving cell, and the first communications device determines a location of the first-type MAC CE in the MAC PDU data packet according to a secondary serving cell corresponding to the first-type MAC CE; and sending, by the first communications device, the MAC PDU data packet to a second communications device, so that the second communications device obtains the first-type MAC CE, and determines, according to the location of the first-type MAC CE in the MAC PDU data packet, the secondary serving cell corresponding to the first-type MAC CE, to obtain information about the secondary serving cell; wherein the determining, by the first communications device, a location of the first-type MAC CE in the MAC PDU data packet according to a secondary serving cell corresponding to the first-type MAC CE comprises: determining, by the first communications device, according to the secondary serving cell corresponding to the first-type MAC CE, a location of each first-type MAC CE in MAC CEs in the MAC PDU data packet, characterised in that each first-type MAC CE is used to carry information about N secondary serving cells, and the determining, by the first communications device, a location of the first-type MAC CE in the MAC PDU data packet according to a secondary serving cell corresponding to the first-type MAC CE comprises: if a first MAC CE in the at least one first-type MAC CE carries information about secondary serving cells whose corresponding cell indexes are (X-1)*N+1 to (X-1)*N+N, determining that the first MAC CE is the X th MAC CE in the MAC PDU data packet. determining, by the first communications device, according to the secondary serving cell corresponding to the first-type MAC CE, a location of each first-type MAC CE in MAC CEs in the MAC PDU data packet, characterised in that each first-type MAC CE is used to carry information about N secondary serving cells, and the determining, by the first communications device, a location of the first-type MAC CE in the MAC PDU data packet according to a secondary serving cell corresponding to the first-type MAC CE comprises: if a first MAC CE in the at least one first-type MAC CE carries information about secondary serving cells whose corresponding cell indexes are (X-1)*N+1 to (X-1)*N+N, determining that the first MAC CE is the X th MAC CE in the MAC PDU data packet.