The invention discloses a mobile terminal and a power supply method thereof. The mobile terminal comprises a first battery, a second battery, a first switching circuit and a second switching circuit which are respectively connected with the first battery and the second battery. The mobile terminal further comprises a control circuit, a voltage detecting circuit and a first determining module. The voltage detecting circuit is used for detecting the first voltage of the first battery and the second voltage of the second battery. The first determining module is used for determining whether the first voltage is higher than a first threshold, if yes, the control circuit is used for switching on the first switching circuit for utilizing the first battery for supplying power to the mobile terminal, and the second switching circuit is switched off; and otherwise, the control circuit is used for switching on the second switching circuit for utilizing the second battery for supplying power to the mobile terminal, and the first switching circuit is switched off. The mobile terminal has a relatively concise power supply circuit structure and therefore realizes low manufacturing cost of the mobile terminal. Simultaneously seamless power supply switching of double batteries is realized through simple components and a concise circuit structure.