The invention belongs to the technical field of two-step-method steelmaking, and in particular relates to a method for increasing molybdenum yield in stainless steel smelting. Stainless steel is smelted by a two-step method using an electric stove and a argon-oxygen furnace. The method has the main technical characteristics of: (1) controlling the carbon content of crude molten steel and ensuringthat the carbon content of the crude molten steel is between 1.2 and 1.6 percent through carbon-proportioning operation; (2) adding 70 to 80 percent of ferromolybdenum needing to be added in an initial stage of a decarburization stage of argon-oxygen furnace smelting; and (3) adding 20 to 30 percent of the ferromolybdenum needing to be added and a reducing agent in a reducing stage of argon-oxygen furnace smelting and keeping alkalinity at over 1.8 in the reducing process. The method can increase the yield of molybdenum to over 97 percent.