The invention relates to a lithium-ion storage battery pack power supply and communication automatic switching method, which adopts a control system circuit composed of an anti-backflow circuit, an output switching control circuit, a charge switching control circuit, a switching detection and control circuit, a lithium-ion battery pack protection circuit, a power supply circuit, an electricity meter, a switching circuit of the electricity meter, and a electricity meter circuit, wherein the electricity meter is used for communicating with an external charger, the electricity meter circuit is used for communicating with a host computer. The control circuit adopted by the method integrates a battery protection function, an electricity meter function, a power supply switching function, a communication switching function and the like, is high in integration degree, has good compatibility, occupies small space, and can realize overcurrent protection, short-circuit protection, low-voltage protection and overcharge protection of the battery pack. The lithium-ion storage battery pack power supply and communication automatic switching method ensures that a system supplies power to electrical equipment in an uninterrupted manner, ensures the safety of circuit automatic control in the absence of external power supply equipment; and the circuit design is safe and reliable, the power consumption is small, the efficiency is high, the cost is low and the application effect is very significant.