An emergency rescue system and a rescue-information judgment method are disclosed. The emergency rescue system includes a plurality of fixed nodes, a dynamic node and a back-end processing platform. Each fixed node has its own fixed node identification. The dynamic node can be a portable device with an emergency illumination module. If the dynamic node is manipulated to broadcast a mayday signal, at least one of the fixed nodes senses the mayday signal. Each fixed node which senses the mayday signal sends the fixed node identification thereof and signal strength of the sensed mayday signal to the back-end processing platform. Thereby, the back-end processing platform calculates and determines a rescue location relative to the dynamic node.