The invention discloses an alarm sound generation method and device and belongs to the field of vehicle alarming.The alarm sound generation method comprises the steps that the to-be-alarmed type of a vehicle is determined; target signal frequency is determined according to the to-be-alarmed type; square wave driving signals are generated to drive a sounder to sound according to the preset pulse width data table and the target signal frequency; the problem of ear-piercing alarming sound is solved; the alarming sound is more relaxed.