The invention provides a circuit board heat conduction optimization design structure for an onboard
aviation product. A heat-conductive board is arranged between a high-power highly-heat-radiating device and a PCB. The heat-conductive board is directly and additionally arranged on the PCB, so that the heat dissipation area is greatly increased; meanwhile, a soft
silica gel heat-conductive fin is additionally arranged between the high-power highly-heat-radiating device and a heat-conductive aluminum plate so that an air gap can be eliminated,
thermal contact resistance between the device and the heat-conductive aluminum plate can be reduced, and heat generated by the device can be rapidly conducted to the heat-conductive aluminum plate. A T-shaped structure of a heat-conductive and
radiation heat exchange face is additionally arranged at the top of the heat-conductive aluminum plate. After the soft
silica gel heat-conductive fin is additionally arranged on the upper end face of the T-shaped structure, the T-shaped structure is connected with a box body sealing cover into a whole, so that heat is effectively conducted to the surface of a box body, and the heat dissipation area is increased. A wedge-shaped pressing mechanism is adopted, so that the contact area between the heat-conductive aluminum plate and the box body is increased, heat conduction is effectively achieved, the temperature of the surface of an electronic device is rapidly lowered, and the service life of the product is prolonged.