The invention discloses a multi-security domain device based on a mobile phone user identification card and an authentication method thereof. The mobile phone user identification card (SIM card) is taken as a personal information security device processing platform, in the SIM software system, the hardware structure of the SIM card is combined, the multi-security domain device is established for storing the data authentication certificate of personal information; through the security and encryption system of the SIM card and a cloud-end application service platform are used to realize personal identity authentication according to a specific authentication algorithm, and after being authorized, services and applications required by users are completed. According to the invention, by utilizing technical features of security, the uncopied performance, uniqueness and the exclusive attribute of the mobile phone user identification card SIM, the SIM card is selected as the carrier of the security domain device, through the card-end authentication and the cloud-end server authentication, the personal information security can be effectively protected.