The invention provides deformable permanent magnet alloy, a deformable permanent magnet alloy thin strip and a preparation method thereof. The deformable permanent magnet alloy comprises the following components in percentage by weight: 65-75 percent of Cu, 15-20 percent of Ni, 7-10 percent of Fe and 1-5 percent of Cr. The preparation method of the deformable permanent magnet alloy thin strip comprises the following steps: weighing the alloy components according to the weight ratio, performing vacuum induction melting on raw materials and casting into a copper-nickel-iron-chromium alloy ingot; forging the alloy ingot; hot-rolling the cast alloy ingot at a temperature of 600-900 DEG C and preparing into the alloy thin strip of 0.1-0.3 mm; tempering the alloy thin strip for 0.5-2 hours at a temperature of 500-650 DEG C. Through the design of the alloy components, a small quantity of Cr is added, so that the oxidation resistance of a permanent magnet material is increased, and meanwhile, the coercive force is increased to a certain degree; the thin strip is prepared through the forging, hot-rolling and tempering processes, so that the processes are simplified, the implantation is easy, and the preparation cost is low.