A method and an apparatus for realizing session identifier synchronization are provided. The method includes initiating a first request for logging into an application program to a server, the first request including a first session identifier, the first session identifier being generated from a login account and an original password of the application program; performing a validity verification on a user of a terminal and sending a verification result that is obtained to the server to allow the server to perform a check on the verification result if the first session identifier is determined to be invalid by the server; and receiving a second session identifier from the server and storing the second session identifier into the terminal if the verification result is verified and approved by the server, the second session identifier being generated from the login account and a new password.