A distress device of lifejacket includes: a lifejacket main body; a wireless emitter, disposed inside the lifejacket main body and including a circuit board and an antenna, wherein the antenna is electrically connected to the circuit board; and a lithium polymer battery, electrically connected to the circuit board and disposed inside the lifejacket main body. Accordingly, the lithium polymer battery can be adopted to replace a convention lithium battery, so that the distress device of lifejacket can be safety disposed in an aircraft for providing sufficient amount of electricity required by the wireless emitter, thereby allowing the distress device of lifejacket to have an additional function of emitting signals, and the research and rescue team is able to rapidly locate the sufferer, so that the distress device of lifejacket is provided with advantages of increasing operation safety and facilitating the locating procedure for search and rescue.