The utility model discloses a greenhouse plant LED light filling device, the interval is provided with a plurality of LED light filling lamps on the light filling lamp support, and light filling lampsupport sets up between two light filling lamp support elevating system, and direction subassembly, light filling lamp fixed plate constitute light filling lamp support, and motor, guide support column, lead screw, spigot nut constitute light filling lamp support elevating system, it is rotatory that the motor drives the lead screw, and the rotatory messenger spigot nut drive direction subassemblyof lead screw reciprocates and then drives light filling lamp support and reciprocates the height with adjustment LED light filling lamp, installs position sensor on the direction subassembly, is provided with light intensity sensor below the LED light filling lamp, and motor, position sensor and light intensity sensor are connected with the singlechip, LED light filling lamp can more steadily bearranged light filling lamp support on, light filling lamp elevating system is vice with the removal that direction subassembly constitution is stable in the light filling lamp support, makes light filling lamp movement track confirm, singlechip and sensor controlling means realize the accurate light filling of adjusting.