A resistance control device and its lamp. The resistance control device includes: a shell, which is provided with an accommodating chamber and the first opening and the second opening connecting the accommodating chamber; and a control module, which includes the resistor and the external plug in the accommodating chamber. The external plug is electrically connected to the resistor. One end of the external plug is set extending the first opening. The external plug is used to connect the resistor to the lamp; and a boosting part, which is connected to the resistor and exposed in the second opening. The boosting part is used to twist or toggle the resistor to adjust the resistance value of the resistor accessing to the lamp. The resistance control device can be removed to achieve the quick separation and assembly of the lamp and improve the use convenience.