Disclosed is a method for processing a SOCKET, a method and an apparatus for transmitting packet data, wherein, the method for processing a SOCKET comprises: a connection management application obtaining a SOCKET identifier corresponding to each service application, and transmitting the SOCKET identifier and a modification instruction to a TCP/IP (Transmission Control Protocol/Internet Protocol) protocol stack; the TCP/IP protocol stack searching for SOCKET file description information corresponding to the SOCKET identifier, and modifying the SOCKET file description information according to the modification instruction. After adopting the technical solution mentioned above, the IP binding operation across applications can be performed on a single-process or multi-process operating system, and the application level traffic selection of the different data connection can be performed according to intention of a user.