Vanadium slag is considered to be a secondary resource of polymetallic symbiosis for the reason that it contains various metal elements such as iron, vanadium, chromium, etc. Currently, a variety of technologies for extracting vanadium and chromium from vanadium slag have been explored in detail. While the treatment of iron in vanadium slag is reported rarely. What's more, a great deal of iron elements cannot be effectively recovered and enter the tailings in the existing research, which leads to the waste of iron resources. For achieving the synergistic recycle of vanadium and iron in vanadium slag, Fe-V alloy was prepared successfully by high-temperature carbothermal reduction smelting with vanadium slag and high-iron red mud. Thermodynamic analysis of the whole reduction system is carried out by using thermodynamic information such as oxygen potential diagram and phase diagram. The result indicates that the oxides of iron and vanadium can be deoxidized easily at high temperature and developed a completely miscible alloy in solid and liquid phases. Therefore, it is feasible to prepare Fe-V alloy in this way. Experimental studies have been made in this work systematically and comprehensively for the effect of raw material ratio on metal recovery rate as well as the impact of adding Na2CO3 and coke on the microstructure and performance of the alloy. The results indicate that the addition of high-iron red mud can improve the basicity of the mixture, and Na2CO3 can improve the reduction conditions of Fe2SiO4 and FeAl2O4, which is beneficial to improving the reduction efficiency of the reaction system. When the addition amounts of Na2CO3 and coke are 8wt% and 30wt%, respectively, the recovery rate of Fe and V in the raw material is the highest. Furthermore, V can promote the pearlite transformation during the solidification, which improves the mechanical properties of the alloy. This work is able to provide a new and reasonable pathway for high value utilization of vanadium slag.