The invention discloses a mobile power supply and an extended function application method of the mobile power supply. Due to the fact that a communication module is arranged on the mobile power supply and the communication module and a communication module built in an external mobile device follow the same wireless communication protocol, wireless communication connection can be set up between the mobile power supply and the external mobile device so that command or data transmission can be conducted and then application of various extended functions is achieved. Due to the adoption of the extended function application method of the mobile power supply, the mobile power supply has the advantages of being capable of providing the practical electric quantity or other information of a batter cell inside the power supply in real time, enabling the external mobile device to be controlled in a remote mode through the mobile power supply, and giving an alarm when the connection is broken and thus preventing the mobile power supply or the mobile device from being lost.