The invention provides an iron cobalt nickel based anti-DC nanocrystalline alloy material and a preparation method thereof. Based on an existing traditional iron-based nanocrystalline soft magnetic alloy formula (Fe73.5Cu1Nb3Si13.5B9), a certain proportion of nickel and cobalt elements are added to overcome nonlinear characteristics caused by excessive initial permeability of amorphous nanocrystalline material, and the novel iron-based amorphous nanocrystalline material has stable magnetic properties and the initial permeability of 1800-6000, and the molecular formula of Fe96-x-y-zCoxNiyCu1Nb3Si0.55zB0.45z, wherein x+y is more than 9 and less than 30, and z is more than 18 and less than or equal to 20. The preparation method is based on a single-roll ultra-cold method, and comprises the steps of mother alloy ingot casting, re-melting, tape making, and strip winding. The iron cobalt nickel based anti-DC nanocrystalline alloy material can satisfy the requirements on various performance indexes including high saturation magnetic induction density, high linearity, low loss and low remanence of soft magnetic material of a current transformer.