The invention relates to steel for a sightseeing ship in deep water and a preparation method of the steel. The steel comprises the following chemical components in percentages by mass: 0.02-0.10% of C, 0.20-0.40% of Si, 0.7-1.20% of Mn, 0.50-1.0% of Cr, 1.7-3.7% of Ni, 1.0-1.7% of Cu, 0.30-0.60% of Mo, 0.02-0.05% of V, 0.02-0.07% of Nb, 0.005-0.015% of Al, less than or equal to 0.020% of P, less than or equal to 0.010% of S, and the balance of Fe and inevitable impurities. The preparation method comprises the following steps: primary degumming, (LF+RH) refining, continuous casting and rolling. The chemical components are optimized, weldability, impact resistance and tensile property of the steel are improved, process parameters in a production process are optimized, cleanliness of liquid steel and component stability are guaranteed, the quality of a casting blank is guaranteed, surface quality and uniformity of a rolled structure are improved, a produced ship board can bear large bearing ability in a using process, and the steel has the advantages of high production efficiency, low cost and the like.