The invention discloses a blade of a steam turbine. The blade of the steam turbine comprises, by mass, 0.1-0.12% of C, 0.5-0.8% of Si, 0.3-0.6% of Mn, 0.01-0.02% of S, 0.1-0.022%Of P, 12-13% of Cr, 0.02-0.06% of Ni, 0.1-0.3% of Cu, 0.2-0.5% of Mo, 0.05-0.36% of W, 0.33-0.55% of V, 0.5-0.8% of Nb, the balance Fe and the balance trace impurities. The invention further provides a process for machining the blade of the steam turbine. The blade of the steam turbine and the process have the advantages that the blade of the steam turbine is long in service life and applicable to working in various harsh environments, the corrosion resistance, the abrasion resistance and the oxidation resistance of the blade can be improved, the cost can be reduced, the cutting property of the blade can be obviously improved, the machining cost can be reduced by the process, and the work efficiency can be enhanced by the process.