The present invention discloses a mobile communications system, which includes a mobile communication device and a server device. The mobile communication device includes a first reception module for obtaining device information corresponding to the mobile communication device and a transmission module for transmitting the device information via a mobile communication network. The server device includes a second reception module for receiving the device information via the mobile communication network and a connection module for establishing a communication connection between the mobile communication device and a destination end according to the device information when a communication request corresponding to the mobile communication device is received from the destination end.