The present application discloses a hand warmer with the function of portable power source, comprising an MCU control module, a heating sheet control module, a mobile power supply control module, and a lithium battery module, wherein the MCU control module is separately connected to the heating sheet control module, the mobile power supply control module and the lithium battery module, and the lithium battery module is further separately connected to the heating sheet control module and the mobile power supply control module. The hand warmer with the function of portable power source has a precise circuit design that allows users to precisely adjust the heating temperature as needed, and is well combined with a mobile power supply.