The invention discloses a preparation method of a travel sleeve of a control rod drive mechanism for a nuclear power plant. The preparation method comprises the following steps: 1) selecting raw materials and obtaining molten steel through electric furnace smelting, AOD refining and LF furnace refining; 2) casting the molten steel into an electrode; 3) carrying out electroslag remelting on the electrode to obtain a steel ingot, wherein in percentage by weight, the steel ingot comprises not more than 0.035% of C, not more than 1.00% of Si, not more than 2.00% of Mn, not more than 0.030% of P, not more than 0.015% of S, 18.50-20.00% of Cr, 9.00-10.00% of Ni, not more than 0.080% of N, not more than 1.00% of Cu, not more than 0.10% of Co, not more than 0.001% of B, not more than 0.05% of Al and the balance of Fe; 4) forging the steel ingot and machining the steel ingot after thermal treatment; 5) obtaining the travel sleeve of the control rod drive mechanism for the nuclear power plant after magnetic performance test and non-destructive test are performed. The travel sleeve of the control rod drive mechanism for the nuclear power plant can satisfy the mechanical property and function requirements of the practical use, and the life satisfies the design specification and national standard requirements. Through measurement of magnetic permeability point by point, the relative magnetic permeability is controlled to be below 1.02.