The invention provides a process method for smelting high purity steel through a VD vacuum treatment device. The method comprises the following steps of KR molten iron desulfuration, wherein it is ensured that before putting into a furnace, S in molten iron is smaller than or equal to 30 ppm; top and bottom combined blowing converter blowing, wherein the mass percent omega [C] of converter tappingC is larger than or equal to 0.08%; external refining and argon refining, wherein in the full process, weak stirring is carried out, and calcium aluminum silicon series slag with the basicity being 2.0 to 4.5 is adopted; and VD treatment, wherein 20 to 35 min VD treatment is adopted, high-vacuum holding of strength is achieved, in the treatment process, according to the strong-weak-strong mode, the bottom stirring argon strength is controlled in a time interval manner, after VD vacuum breaking, a manner that soft blowing is adopted, large-particle inclusions are removed, molten steel is subjected to standing, and small particle inclusions are removed is adopted for further improving the molten steel purity. It is known that through the particular VD treatment process stirring control modeis adopted for assisting with a proper refining slag system and a soft blowing operation method, molten steel slag entrapment can be effectively reduced, the removing effect of non metal inclusions can be improved, and the method is suitable for production of various low, middle and high carbon steel with the carbon content being 0.15 to 1.05%.