A user service processing method, comprising: sending, by a policy control device, a request message to a charging processing device; receiving, by the policy control device, a response message sent by the charging processing device, wherein the response message carries related information of a first quota management mode of a user or a user service; determining, by the policy control device, the first quota management mode of the user service based on the related information of the first quota management mode of the user or the user service; generating, by the policy control device, a first policy of the user service of the user, and sending the first policy to a session management function device, wherein the first policy indicates to perform the first quota management mode on the user service; receiving, by the policy control device, related information, that is sent by the charging processing device and that is used for changing the first quota management mode, of a second quota management mode of the user or the user service; determining the second quota management mode of the user service based on the related information of the second quota management mode of the user or the user service; and generating, by the policy control device, a second policy of the user service, wherein the second policy is for updating or replacing the first policy and for indicating to perform the second quota management mode on the user service; characterized in that: the first quota management mode is a first initial quota request mode, the second quota management mode is a second initial quota request mode, the first initial quota request mode is a blocking mode, and the second initial quota request mode is a non-blocking mode; or the first initial quota request mode is a non-blocking mode, and the second initial quota request mode is a blocking mode; in the blocking mode, the session management function device is to start the user service only after having received a quota granted by the charging processing device for the user service; and in the non-blocking mode, the session management function device is to start the user service before requesting the quota from the charging processing device for the user service, or to request the quota from the charging processing device for the user service while starting the user service. sending, by a policy control device, a request message to a charging processing device; receiving, by the policy control device, a response message sent by the charging processing device, wherein the response message carries related information of a first quota management mode of a user or a user service; determining, by the policy control device, the first quota management mode of the user service based on the related information of the first quota management mode of the user or the user service; generating, by the policy control device, a first policy of the user service of the user, and sending the first policy to a session management function device, wherein the first policy indicates to perform the first quota management mode on the user service; receiving, by the policy control device, related information, that is sent by the charging processing device and that is used for changing the first quota management mode, of a second quota management mode of the user or the user service; determining the second quota management mode of the user service based on the related information of the second quota management mode of the user or the user service; and generating, by the policy control device, a second policy of the user service, wherein the second policy is for updating or replacing the first policy and for indicating to perform the second quota management mode on the user service; the first quota management mode is a first initial quota request mode, the second quota management mode is a second initial quota request mode, the first initial quota request mode is a blocking mode, and the second initial quota request mode is a non-blocking mode; or the first initial quota request mode is a non-blocking mode, and the second initial quota request mode is a blocking mode; in the blocking mode, the session management function device is to start the user service only after having received a quota granted by the charging processing device for the user service; and in the non-blocking mode, the session management function device is to start the user service before requesting the quota from the charging processing device for the user service, or to request the quota from the charging processing device for the user service while starting the user service.