The invention relates to laser cladding powder for 30CrMnSiNi2A steel and a preparation method. The laser cladding powder is prepared from the following components in weight percent: 0.8% to 1.0% of Cr, 0.75% to 1.10% of Mn, 0.65% to 1.10% of Si, 2.0% to 3.2% of Ni, 0.16% to 0.22% of C, 0.15% to 0.20% of Cu, 0.015% to 0.020% of P, 0.01% to 0.015% of S, 0.001% to 0.015% of rare earth and the balance of Fe. The invention further provides the preparation method of the laser cladding powder, the laser cladding powder is exclusively used in a laser cladding technique of the 30CrMnSiNi2A steel, excellent bonding strength and low metallurgical defects and dilution rate of a cladding interface are guaranteed, the toughness of a cladding layer is increased, the wettability of the cladding powder is improved, the cracking of the cladding layer is inhibited, and the crack growth rate is reduced.