Data transmission system and method

The invention fits for network communication field, and provides a data transmission system and method; said system includes re-direction server and at least one transferring servers which is connected with the re-direction server, the re-direction server which is used to receive data transmission request message of client, select the transferring server which transfers data based on IP address of source client and destination client took by message; and transferring server which is used to receive data of source client and transfer said data to the destination client, said transferring server possesses at least two net cards, IP address of different net cards are corresponding with different networks. By the invention, the multiple net cards transferring server provides data transferring service for client, data transmission quality between clients is increased.