The invention relates to the field of building construction, and provides a stair landing plate which comprises a cast-in-place concrete plate and reinforcing steel bars distributed in the cast-in-place concrete plate. Prefabricated concrete cushion blocks with the inverted trapezoidal side faces are further included, and the distribution and the number of the concrete cushion blocks on the stair landing plate are determined by the number of supporting rods for supporting a formwork. The invention further discloses a construction method for the stair landing plate. The construction method comprises the steps that a, the thickness of the stair landing plate, the mark of concrete and the distance of steel bars are determined according to a drawing; b, the dimension for manufacturing the concrete cushion blocks by the concrete is determined step by step according to the plate thickness and the steel bars, and the concrete cushion blocks are manufactured by the concrete with the same mark or the high mark; c, in the formwork erecting process of the stair landing plate, a formwork supporting rack is supported on the concrete cushion blocks. According to the construction method of the stair landing plate, a frame supporting system is reinforced, the integrality of construction of the landing plate is improved, materials on a construction site are saved, later period repairing of floor plates is avoided, and meanwhile the height of a plate face is controlled.