The invention relates to a manufacturing method for a magnetic object, in particular to a Fe-Ni alloy soft magnetic material with magnetic permeability mu of 125 and a manufacturing method for the Fe-Ni alloy soft magnetic material. The Fe-Ni alloy soft magnetic material with magnetic permeability mu of 125 is molded by the following components through compression: Fe-Ni powder which consists of 40 to 60 weight percent of Ni and the balance of Fe, phosphoric acid in an amount which is 0.8 to 1.2 percent based on the weight of the Fe-Ni powder and phenolic resin in an amount which is 0.5 to 1.0 percent based on the weight of Fe-Ni powder, wherein the phosphoric acid is used for surface treatment for the Fe-Ni powder. The invention has the advantages that: 1, the manufacturing process and use equipment are simple; 2, due to the adoption of Fe-Ni powder with low price, the production cost is greatly reduced; 3, products manufactured by the method have high inductance, relative high quality factors and low power loss value; and 4, under the condition of relative high temperature, Fe-Ni alloy has high soft magnetic performance.