The invention relates to a steel-concrete combination deck plate and a construction method thereof, wherein the steel-concrete combination deck plate comprises: bottom steel plates arranged on steel girders, wherein the bottom steel plates in the bearing regions of the steel girders are bent in shape, and the bottom steel plates are 8-10 mm in thickness; a plurality of shear plates vertically connected to the bottom steel plates; a concrete tier including reinforcement fabric penetrating through the shear plates, wherein the concrete tier is cast to the bottom steel plates, and the combination deck plate is 10-15 cm in thickness. The steel-concrete combination deck plate uses the bottom steel plates as stress-bearing parts as well as a formwork for a cast-in-place desk concrete tier, and steps of mounting and releasing concrete formwork are omitted; the shear plates serve as stiffeners for the bottom steel plates, good combination of the bottom steel plates with the concrete tier can be guaranteed, and cracking of the concrete tier is prevented; the deck thickness is controlled to 10-15 cm and is reduced, the weight is 25% and above lower than that of a composite beam deck system, dead load is reduced, crossing ability, structural strength and durability of the main structure are improved, construction input is reduced, and the efficiency of a construction method is high.