A method of cell reselection for a mobile communication system, characterized by: a mobile device in the mobile communication system determining whether is it is capable of initiating an emergency call through a second cell according to a plurality of access classes when a network of the mobile communication system restricts the mobile device from accessing a first cell, and the mobile device performing a first cell reselection procedure to switch from the first cell to the second cell, so as to generate a first determination result; and the mobile device determining whether to camp on the second cell according to the first determination result, comprising: the mobile device entering an any cell selection procedure to find an acceptable cell to camp on when the first determination result indicates that the mobile device is incapable of initiating the emergency call through the second cell; the mobile device further determining whether capable of initiating normal access through the second cell according to the plurality of access classes so as to generate a second determination result when the first determination result indicates that the mobile device is capable of initiating the emergency call through the second cell; and the mobile device determining whether to camp on the second cell according to the second determination result. a mobile device in the mobile communication system determining whether is it is capable of initiating an emergency call through a second cell according to a plurality of access classes when a network of the mobile communication system restricts the mobile device from accessing a first cell, and the mobile device performing a first cell reselection procedure to switch from the first cell to the second cell, so as to generate a first determination result; and the mobile device determining whether to camp on the second cell according to the first determination result, comprising: the mobile device entering an any cell selection procedure to find an acceptable cell to camp on when the first determination result indicates that the mobile device is incapable of initiating the emergency call through the second cell; the mobile device further determining whether capable of initiating normal access through the second cell according to the plurality of access classes so as to generate a second determination result when the first determination result indicates that the mobile device is capable of initiating the emergency call through the second cell; and the mobile device determining whether to camp on the second cell according to the second determination result. the mobile device entering an any cell selection procedure to find an acceptable cell to camp on when the first determination result indicates that the mobile device is incapable of initiating the emergency call through the second cell; the mobile device further determining whether capable of initiating normal access through the second cell according to the plurality of access classes so as to generate a second determination result when the first determination result indicates that the mobile device is capable of initiating the emergency call through the second cell; and the mobile device determining whether to camp on the second cell according to the second determination result.