The invention relates to a frame structure of an LED side-emitting panel lamp. The frame structure of the LED side-emitting panel lamp can achieve a certain protecting effect on a light guide plate and a heat dissipation strip and is convenient to mount and demount. The thicknesses of the inner walls of U-shaped grooves of the frame structure are larger than those of the outer walls of the U-shaped grooves, and thus the situation that in the mounting process, due to the influence of factors such as thermal expansion and cold contraction, the inner walls of the U-shaped grooves extrude the light guide plate and the heat dissipation strip, and the production quality is affected can be avoided; through a connecting structure full of creativity, the mounting and demounting efficiency is improved, and manual rapid mounting and demounting can be conducted without tools such as a screwdriver; the whole frame structure is high in connecting stability, physical damage of screw drilling to a back plate and a rear cover plate is greatly reduced, the product quality is improved, and the service life of a product is prolonged; and a screw hole structure is omitted, and thus the undesirable phenomena, such as stress concentration, of the rear cover plate are avoided.