A linear luminance adjusting circuit includes a rectifying circuit, a constant voltage circuit, a control module, a linear constant current circuit and a hybrid luminance circuit. The rectifying circuit rectifies power from the AC power source to generate a rectified voltage. The constant voltage circuit transforms the rectified voltage into a constant voltage. The control module is electrically coupled to the constant voltage circuit. The control module generates a control signal using the constant voltage. The linear constant current circuit is electrically coupled to the rectifying circuit and the control module. The linear constant current circuit is powered up using the rectifying voltage. And the linear constant current circuit generates a linear current using the control signal. The hybrid luminance circuit is electrically coupled to the rectifying circuit and the linear constant current circuit. The hybrid luminance circuit illuminates using the linear current.