Abstract: In order to solve the poor grindability of electric furnace steel slag, the reduction of electric furnace steel slag is studied by using theoretical calculation combined with vacuum carbon thermal reduction. The changes of each component in the electric furnace steel slag with the increase of reduction temperature were determined by theoretical calculation, and the reduction temperature range of the vacuum carbon-thermal reduction experiment was set. The experimental results show that with the increasing reduction temperature, the self-pulverization effect of electric furnace steel slag shows a trend of first increasing and then decreasing, while Fe is continuously reduced and shows an obvious aggregation effect, which is conducive to subsequent separation and recovery. The optimal reduction conditions were as follows: carbon content of 16%, alkalinity R=1, heat preservation for 60 min, the self-pulverization rate of electric furnace steel slag reached 93.8% at 1450℃, and the proportion of particles with a particle size of less than 89.2 μm in the sample was as high as 90%. Compared with the traditional research on the self-pulverization of electric furnace steel slag, the self-pulverization rate of electric furnace steel slag only reaches 49.97% when the reduction temperature is as high as 1600℃ in an atmospheric air atmosphere, and the vacuum carbon thermal reduction has the obvious advantages of high pulverization rate and low reduction temperature.