The invention relates to a hidden-frame flat-panel solar energy collector, belonging to the solar energy equipment field. The hidden-frame flat-panel solar energy collector is characterized in that an absorber plate core is arranged in a frame of the collector. A glazing cover on the front of the solar energy collector is positioned and supported by a step-like insulation side board of the collector and is sealed and bonded on the frame by glue. The periphery of the glazing cover on the front of the solar energy collector is sintered or coated with a ray-prevention coating. A protective decorating backboard which is composed of plates of safety glass, aluminum plastic plate, and the like and is arranged on the back side of the collector can also be sealed and bonded on the frame by the glue. The frame of the collector is provided with an erect protective edge. The glazing cover of the collector is positioned by the step-like insulation side board and is bonded on the frame of the collector by the sealing bond glue. A glass surface with a metal line margin is arranged on the front of the collector and is beautiful and elegant.