The invention relates to a water induction alarm. The water induction alarm has the main function of detecting people swimming in lakes which are forbidden to swim. The water induction alarm has the main detection mode that the alarm is provided with an inductor for inducing the temperature of a human body, and a sound alarm can be given when people approach water in a certain range; and a lamp onthe inductor flickers to give an alarm, so that pedestrians are prevented from being panic due to sound at night. If the alarm sound is long in time and people do not leave, the position is positioned to related supervisors for checking.