Abstract: A linear constant-current LED drive circuit adaptive to a wide voltage range includes a rectifier bridge used for full-wave rectification of the waveform of a sinusoidal voltage and connected with a filter circuit and a high-voltage stabilizing and dropping circuit through wires, the filter circuit used for converting a full-wave pulsating voltage output by the rectifier bridge into a direct-current voltage and connected with a constant-current source circuit through a wire, the constant-current source circuit used for limiting a current across LED loads and providing a constant-current power supply for LED lights and connected with a switch array circuit through a wire, and the switch array circuit used for switching series-parallel connection modes of LED light strings by means of the switching characteristics of LDMODs when an external voltage varies. The high-voltage stabilizing and dropping circuit provides a working voltage for low-voltage modules.