The invention provides a multifunctional portable power supply, comprising a li-ion battery pack which can be charged or discharged and connected in parallel. The li-ion battery pack is sequentially connected with a li-core fourfold protection circuit and a charging management circuit through leads; meanwhile, the li-ion battery pack are connected with a battery capacity indicating circuit through the leads; when being charged, the li-ion battery pack which is connected with the li-core fourfold protection circuit is charged by connecting an adaptive charger with the charging management circuit; when being discharged, the li-ion battery pack discharges for external electronic equipments through a DC-DC conversion circuit and provides power for a multifunctional extension circuit through the DC-DC conversion circuit. The multifunctional potable power supply which is provided with the invention has fourfold protection techniques (overcharging, over-discharging, over-heating and over-current protection), DC-DC conversion technique (DC-DC conversion), management of intelligent charging (four-stage charging method such as tiny current charging, constant current charging, constant voltage charging, maintaining charging, etc.), and multifunctional extensions (highlighted illuminance, outdoor alarming and field mosquito repelling effect).