The utility model discloses a portable plug -and -play chromatic harmonica heater, including temperature detect switch, be used for the joint at the U -shaped card slot of chromatic harmonica bottom with be used for the heating wire for the chromatic harmonica heats, the both sides of the U type mouth that the heating wire was fixed at U -shaped card slot, temperature detect switch fixes in U -shaped card slot, the heating wire is connected with temperature detect switch, temperature detect switch is connected with the USB connecting wire that is used for pegging graft on the power. The utility model provides a portable plug -and -play chromatic harmonica heater design benefit can make things convenient for the ground joint on the chromatic harmonica, and the heating wire is just in time hugged closely the mouth organ spring plank and is given the spring plank with heat conduction, can avoid the chromatic harmonica mucomembranous problem to appear in the performance, makes the chromatic harmonica also can not take place mucosa problem than continuously playing any musical instrument under the cold environment. Simultaneously, this heater passes through the USB power supply, and is nimble convenient.