The invention provides a temperature early warning apparatus. The temperature early warning apparatus comprises a liquid-cooling flat tube, at least one thermosensitive element, a temperature analysis unit used for monitoring the corresponding thermosensitive element to analyze the internal temperature of a battery module, and an early warning unit; a power supply apparatus adopting the temperature early warning apparatus comprises the battery module; the liquid-cooling flat tube is wound in the battery module; and the corresponding thermosensitive element is arranged in a corresponding mounting groove in the liquid-cooling flat tube, and is wound in the battery module along with the liquid-cooling flat tube so as to monitor the temperature of the battery module. By adoption of the designed temperature early warning apparatus and the power supply apparatus, the temperature of the batteries on the periphery can be monitored while the temperature of the internal single batteries can be effectively monitored as well; the monitoring value of the corresponding thermosensitive element changes along with the changes of the temperature of the battery module; and when the temperature analysis unit works out that the temperature of the battery module exceeds a preset threshold value through analysis according to the monitoring value, the early warning unit is triggered to give out an early warning signal so as to remind a driver to take measures in time and to rapidly evacuate to a safe area.