A charging method for a terminal being accessed through multiple access networks, characterized by: after the terminal establishes one IP Connectivity Access Network, IP-CAN, session with a packet data network through the multiple access networks simultaneously to transmit different data flows of one or more services in different access networks (301, 317), when the terminal accesses a service which comprises at least two data flows to be transmitted, an Application Function, AF, sending an application message to a Policy and Charging Rules Function, PCRF, wherein the application message carries an IP address of the terminal; the PCRF receiving the application message from the AF, and acquiring that the terminal has established said one IP-CAN session through the multiple access networks simultaneously according to the IP address of the terminal; the PCRF determining to transmit the data flows through different access networks, wherein each of the data flows is identified by a corresponding flow identifier; and sending a message to notify the AF an IP-CAN Type parameter of each access network connection passed through by each of data flows of the service accessed by said terminal and the corresponding flow identifier of said each of data flows; said AF sending said IP-CAN Type parameter and said corresponding flow identifier to a charging subsystem; and said charging subsystem identifying the data flow according to said corresponding flow identifier, and charging differently for the data flows passing through different access network connections of said terminal according to corresponding IP-CAN Type parameters (310, 324). after the terminal establishes one IP Connectivity Access Network, IP-CAN, session with a packet data network through the multiple access networks simultaneously to transmit different data flows of one or more services in different access networks (301, 317), when the terminal accesses a service which comprises at least two data flows to be transmitted, an Application Function, AF, sending an application message to a Policy and Charging Rules Function, PCRF, wherein the application message carries an IP address of the terminal; the PCRF receiving the application message from the AF, and acquiring that the terminal has established said one IP-CAN session through the multiple access networks simultaneously according to the IP address of the terminal; the PCRF determining to transmit the data flows through different access networks, wherein each of the data flows is identified by a corresponding flow identifier; and sending a message to notify the AF an IP-CAN Type parameter of each access network connection passed through by each of data flows of the service accessed by said terminal and the corresponding flow identifier of said each of data flows; said AF sending said IP-CAN Type parameter and said corresponding flow identifier to a charging subsystem; and said charging subsystem identifying the data flow according to said corresponding flow identifier, and charging differently for the data flows passing through different access network connections of said terminal according to corresponding IP-CAN Type parameters (310, 324).