A method applied to an embedded subscriber identity module (eSIM) module includes: storing a first device identity sent by a first processing module; receiving, after detecting that the eSIM module is powered off and then powered on, device check information sent by a second processing module; decrypting a second device identity from the device check information; in response to the first device identity being the same as the second device identity, normally performing a mobile communication service; and in response to the first device identity being different from the second device identity, or in response to the eSIM module not receiving the device check information sent by the second processing module after detecting that the eSIM module is powered off and then powered on, forbidding the eSIM module from performing the mobile communication service.