The invention relates to steel for a hydraulic breaking hammer piston and a manufacturing technology of the steel. The steel for the hydraulic breaking hammer piston is high-alloy steel SNCM26VMOD andmainly comprises the chemical components of, by weight, 0.14-0.25% of C, 0.15-0.35% of Si, 0.80-1.20% of Mn, 3.25-3.65% of Ni, 1.40-1.80% of Cr, 0.40-0.60% of Mo, 0.05-0.15% of V, 0-0.025% of S, 0-0.025% of P, and the balance Fe and inevitable impurity elements. The manufacturing technology of the steel for the hydraulic breaking hammer piston comprises the steps of electric-arc furnace smelting,LF refining, VD refining, electroslag remelting, forging and heat treatment after forging. The high-strength high-toughness piston material is manufactured through the steel and the manufacturing technology, the situation that the center of the piston is sunken is avoided, the piston breaking situation is greatly decreased, and the service life of the piston is prolonged.