A security system and method for an electronic device include comparing data in a Subscriber Identity Module (SIM) card with data in a virtual SIM card, if the virtual SIM card is not blank. The security system further include determining whether the electronic device has received a command of reporting loss of the SIM card from the network server, if the data in the SIM card is the same as the data in the virtual SIM card. The security method further includes running the electronic device normally if the electronic device has not received the command of reporting loss of the SIM card. If the command of reporting loss is received, a contact list and message of the electronic device are deleted and a calling function of the electronic device is disabled.