Abstract: An emergency power supply starting system a lithium battery with automatic preheating function, including a lithium battery pack, an output control module, an output module, a working power supply control module, a CPU master control module, an operation panel display function module, a heater control module, a heater module, an information sampling module and a charging module is disclosed. The CPU master control module, monitoring the real-time temperature, residual capacity and user operation status of the lithium battery pack, cuts off all output functions and charges the lithium battery (power supply is resumed only after charging) if the battery voltage is too low; if the voltage is normal but battery temperature is too low, the heater control module will start the heater module to initiate the heating process driven with the low current from the lithium battery and the latter is ready for use after the lithium battery temperature returns to normal.