The invention discloses a damp-proof potentiometer which comprises a shell .The shell comprises a lower shell body and an upper shell body .The shell is composed of an inner metal layer and an outer damp-proof layer .A shaft sleeve is arranged on the top of the upper shell body .A cavity is formed between the upper shell body and the lower shell body .A rotating shaft, an electric conduction rotating piece, a first fixed pin connection piece, a second fixed pin connection piece, a movable pin connection piece and an arc resistor are arranged inside the cavity .The rotating shaft is matched with the shaft sleeve .The rotating shaft comprises an inner metal core and an outer graphite layer .The first fixed pin connection piece and the second fixed pin connection piece are connected to the two ends of the arc resistor respectively .In this way, the damp-proof potentiometer has the good dampness resistance and good lubrication level, and effectively prevents external dampness from invading the potentiometer.