An exemplary testing device for testing quality of indicator lights includes a light intensity tester and a control unit electrically connected to the light intensity tester. The light intensity tester includes a testing circuit, and the testing circuit is capable of generating testing parameters of corresponding indicator lights. The control unit is capable of providing electric energy to the indicator lights. The testing parameters from the testing circuit are changed according to light intensity of the indicator lights and are then transmitted to the control unit. Thus, the control unit is capable of comparing the testing parameters with predetermined parameters to detect the quality of the indicator lights.