A lighting device having replaceable intelligent sensor includes a filter, a first voltage converter, a DC-to-DC converter, an intelligent sensor, a control circuit, a load and a rectifier. The first voltage converter is connected to the filter. The DC-to-DC converter is connected to the first voltage converter. The intelligent sensor is detachably connected to the DC-to-DC converter. The control circuit is connected to the filter, and includes an optical coupler and a switch connected to each other. The load is connected to the control circuit. The rectifier is connected to the filter and an external power source in order to drive the intelligent sensor and the control circuit. The intelligent sensor generates a first control signal to control the optical coupler to turn on the switch, such that the control circuit generates a driving signal to drive the load.