A heatsink assembly structure combined with a heat-generating element disposed on a circuit board is provided. The heatsink assembly structure includes a heat conducting plate and at least one spring plate. The heat conducting plate includes a pressing surface and an abutment surface. The spring plate includes at least one fixing section and a plurality of pressing sections extending from the fixing section. When the fixing section of the spring plate is fixed to the circuit board, each of the pressing sections applies a force to press the heat conducting plate towards the heat-generating element, so as to attach the abutment surface on the heat-generating element, and conduct heat generated by the heat-generating element to the heat conducting plate. Thus, a plurality of forces pressing the heat conducting plate downward is provided with a simple structure.