Disclosed are a heat sink fixing structure and a board-level heat dissipation apparatus. The heat sink fixing structure comprises a support structure and a floating structure; the support structure comprises a first support member for providing support for the semiconductor component and a second support member spaced apart from the first support member; the heat sink is arranged corresponding to the semiconductor component and is connected to the second support member in a floating configuration. The first support member supports the semiconductor component, and the second support member supports the heat sink, so that the heat sink and the semiconductor component are separated and arranged, so as to reduce the number of openings near the semiconductor component on the integrated circuit board, thereby reducing the wiring difficulty of the integrated circuit board, reducing the stress borne by the integrated circuit board at the same time, and improving long-term reliability. Furthermore, the heat sink and the second support member are connected in a floating manner by means of a floating structure, so that the heat sink is adapted to semiconductor components of different heights and tolerances, thereby effectively reducing the temperature of the semiconductor components and improving the long-term reliability thereof.