The mineral phases of the clinker obtaining after oxidizing vanadium slag with high contents of Ca and P are analyzed by X-ray diffraction (XRD), and the experimental parameters of vanadium extraction are also investigated in this paper. The results show that V exists in the form of Na4V2O7, Na3VO4, Na1.33V2O5 and NaCaVO4 when the amount of added Na2CO3 is relatively small (35%). But, with the added Na2CO3 amount increasing, Na4V2O7 and NaCaVO4 react with Na2CO3, then change into Na3VO4. P in the clinker exists in the form of Na3PO4. The leaching rate of vanadium can reach above 90% under the conditions: added Na2CO3 amount of 40%, liquid to solid ratio of 5∶1 mL/g, leaching temperature of 90℃, leaching time of 4 min, stirring rate of 150 r/min. Therefore, the method of extracting vanadium from molten vanadium slag with high contents of Ca and P by direct oxidation and adding Na2CO3 and water leaching is feasible.