A network authentication method and a system based on an eye tracking procedure are provided. An image capturing unit of a user terminal captures a face image sequence of a user, and transmits the face image sequence to a server terminal such that the server terminal executes an authentication procedure to return an authentication result. The user terminal executes an eye tracking procedure based an eye movement of the user. The user terminal transmits an emergency signal to the server terminal if the user terminal determines that an emergency mode is triggered during the eye tracking procedure.