A charging control method, comprising: generating, by a charging trigger apparatus, CTF, a resource quota request according to a trigger condition; and sending the resource quota request to an online charging system, OCS, so that the OCS determines a quota type and the number of quota of the quota type after receiving the resource quota request, and allocates a quota for the resource quota request according to the quota type and number determined by the OCS; wherein the generating, by a CTF, a resource quota request according to a trigger condition comprises: after the trigger condition is met, if the CTF determines that a first message is received from a policy and charging control module, PCRF, and carries a service unit type wherein the service unit type is used to indicate a quota type to be carried in the resource quota request to be generated by the CTF, determining, by the CTF, the number of quota of the quota type according to the service unit type; and generating the resource quota request according to the service unit type and the number, wherein the resource quota request comprises the quota type indicated by the service unit type and the number of quota of the quota type; receiving, by the CTF, a response message sent by the OCS, where the response message includes the quota allocated for the resource quota request; controlling, by the CTF, a service according to the quota allocated by the OCS, and monitoring use of the quota; receiving, by the CTF, a second message sent by the PCRF, wherein the second message carries a service unit type; and if a quota corresponding to the second message does not exist in the CTF, applying for a quota, from the OCS, corresponding to the second message according to the service unit type in the second message. generating, by a charging trigger apparatus, CTF, a resource quota request according to a trigger condition; and sending the resource quota request to an online charging system, OCS, so that the OCS determines a quota type and the number of quota of the quota type after receiving the resource quota request, and allocates a quota for the resource quota request according to the quota type and number determined by the OCS; wherein the generating, by a CTF, a resource quota request according to a trigger condition comprises: after the trigger condition is met, if the CTF determines that a first message is received from a policy and charging control module, PCRF, and carries a service unit type wherein the service unit type is used to indicate a quota type to be carried in the resource quota request to be generated by the CTF, determining, by the CTF, the number of quota of the quota type according to the service unit type; and generating the resource quota request according to the service unit type and the number, wherein the resource quota request comprises the quota type indicated by the service unit type and the number of quota of the quota type; receiving, by the CTF, a response message sent by the OCS, where the response message includes the quota allocated for the resource quota request; controlling, by the CTF, a service according to the quota allocated by the OCS, and monitoring use of the quota; receiving, by the CTF, a second message sent by the PCRF, wherein the second message carries a service unit type; and if a quota corresponding to the second message does not exist in the CTF, applying for a quota, from the OCS, corresponding to the second message according to the service unit type in the second message. after the trigger condition is met, if the CTF determines that a first message is received from a policy and charging control module, PCRF, and carries a service unit type wherein the service unit type is used to indicate a quota type to be carried in the resource quota request to be generated by the CTF, determining, by the CTF, the number of quota of the quota type according to the service unit type; and generating the resource quota request according to the service unit type and the number, wherein the resource quota request comprises the quota type indicated by the service unit type and the number of quota of the quota type; receiving, by the CTF, a response message sent by the OCS, where the response message includes the quota allocated for the resource quota request; controlling, by the CTF, a service according to the quota allocated by the OCS, and monitoring use of the quota; receiving, by the CTF, a second message sent by the PCRF, wherein the second message carries a service unit type; and if a quota corresponding to the second message does not exist in the CTF, applying for a quota, from the OCS, corresponding to the second message according to the service unit type in the second message.