The invention discloses a route area update (RAU) index information acquisition method and device, relating to the field of mobile communication and solving the problem that the index information acquisition is time-consuming and labor-consuming in the process of analyzing the RAU flow. The method includes acquiring the data packet through a Gb port; parsing the acquired data packet according to the Gb port protocol specification and identifying the RAU signaling including a route area update request signaling, route area update accepting signaling, and route area update rejection signaling; and extracting the field information in the RAU signaling and obtaining the index information of the RAU flow based on the field information. The acquisition method and device are mainly used by service providers in the process of analyzing the RAU flow of a mobile station MS.