The invention relates to a low-core loss FeSiAlNi-based composite soft magnetic material and a preparation method thereof. According to the material, a ZnFe2O4-coated magnetic powder layer and a silicon resin layer sequentially coat the outside of Fe85Si8Al4Ni3 from inside to outside. The low-core loss FeSiAlNi-based composite soft magnetic material has the advantages of high permeability and lowcore loss. The low-core loss FeSiAlNi-based composite soft magnetic material can be molded according to the actual desired shape in use, has obvious advantages when an anisotropic material is prepared, and is simple in operation, free of cutting and free of a leftover material, and the cost is reduced. The synthesis method is simple, low in cost and mild in reaction condition. A laser particle size test result shows that D50 of the Fe85Si8Al4Ni3 powder obtained through gas atomization is about 36 microns.