The invention relates to a seat mounting structure, which can protect the neck of a passenger against being injured when in rear-end collision and comprises two front mounting supports and two rear mounting supports. The two front mounting supports and the two rear mounting supports are fixedly arranged below a seat, the two front mounting supports are respectively fixedly disposed on the left side and the right side of the front end of the automobile seat, the two rear mounting supports are respectively fixedly arranged on the left side and the right side of the rear end of the automobile seat, both the two rear mounting supports are hinged with an automobile floor, a supporting frame which is fixed onto the automobile floor are arranged below the two front mounting supports, connecting holes are disposed on the front mounting supports, movable pins are arranged in the connecting holes, two ends of each movable pin are provided with limiting structures, pin holes which are aligned with the connecting holes are arranged on the supporting frame, and a compression spring is sleeved on each movable pin and positioned between the corresponding pin hole and the limiting structure, which is close to the automobile floor, of the movable pin. The seat mounting structure has the advantages that the integral automobile seat can rearwards turn within a small range after the rear end collision, collision impact force is absorbed, and the neck of the passenger is protected against being injured.