The invention discloses a vanadium slag preparation method and belongs to the field of puddling. The method comprises the steps of firstly, crushing stone coal and solid carbon, mixing the stone coal and the solid carbon with iron ore, binder, calcium carbonate and the like uniformly, preparing balls or blocks, conducting the drying, adding all materials into a dedicated electric induction furnace, and discharging molten iron containing vanadium and slag in the form of liquid state, wherein conducting blowing on ferrovanadium, so that vanadium slag and steel are formed; conducting fine grinding on the slag after cooling down, and then separating out granular zero-valent iron. Each ball or block comprises 30-80% of the iron ore, 3-55% of the stone coal, 10-40% of the solid carbon, 0.5-15% of the binder and 0.5-35% of the calcium carbonate. The power supply of the dedicated electric induction furnace is intermediate frequency or high frequency induction power supply, and a crucible is made of heat resisting metal or graphite. Water-cooling coil are arranged at the outer side of the crucible, and the total height of the coils is smaller than that of the crucible. A dust collector is arranged over the crucible, and an automatic feeder is arranged between the dust collector and the crucible and used for adding the balls or blocks; the carbon-contained balls or blocks can be added into the electric induction furnace separately or together with metal furnace charge. According to the vanadium slag preparation method, high-quality ilmenite and large-size furnaces such as a blast furnace and an electric furnace are not needed to be used, the processing equipment is simple, the production procedure is short, and the raw material cost is low.