The embodiment of the invention provides an LED panel lamp. The LED panel lamp comprises a back plate, reflector paper, a light guide plate, a diffusion plate, light source assemblies and a frame assembly. The frame assembly comprises a frame and a movable plate, the movable plate is movably assembled on the inner side of the frame, and an extrusion space is formed between the opposite surfaces of the movable plate and the frame; and an expansion piece is assembled in the extrusion space, and the movable plate moves towards the center of the frame through the extrusion counter force of the expansion piece. The back plate is arranged in a covering mode and fixed to the top of the frame. The diffusion plate, the light guide plate and the reflector paper are sequentially arranged between supporting parts of the frame and the back plate in a laminating mode, and the reflector paper is tightly attached to the inner side of the back plate. The light source assemblies are assembled on the side surface, facing the light guide plate, of the movable plate. Each light source assembly comprises an aluminum substrate, an LED light source and partition strips arranged on the two sides of the LED light source in a spaced mode. The LED light sources and the partition strips are arranged on the aluminum substrates. The partition strips are attached to the ends of the light guide plate, and the thickness of the partition strips is larger than that of the LED light sources. A gap is formed between the end of the light guide plate and the end of each LED light source.