The invention provides a gradient composite material steel rail turnout coating prepared by laser cladding. The composite material is characterized in that a transition layer adopts a Fe-based alloy material, wherein the Fe-based alloy material comprises the following components of, in percentage by weight, 13wt%-17wt% of Cr, 3wt%-6wt% of Ni, 1wt%-1.5wt% of Si, 0.5wt%-1wt% of Mn, 0.3wt%-1.2wt% ofNb, 1wt%-1.5wt% of B, 0.05wt%-0.7wt% of C, 0.5wt%-1.2wt% of V, and the balance Fe; a strengthening layer is arranged above the transition layer, and the strengthening layer adopts a Fe-based metal nano-phase composite material. The preparation method comprises the following steps of preparing the Fe-based metal powder and the Fe-based metal nano-phase composite material coating; preheating a steelrail by using laser scanning heating so as to reduce the temperature gradient; preparing the gradient composite material coating on the surface of the steel rail by utilizing a laser cladding technology, and performing laser scanning heat treatment; and reducing the cooling rate after laser cladding, so that the martensite of the heat affected zone is prevented from being generated, and the cracking property of the coating is reduced. The prepared steel rail frog has the advantages that the hardness curve is smooth, the overall toughness and bearing performance are good, the strength and hardness is higher than a common heavy-load railway frog, the service life is longer, and manufacturing integration is relatively strong.