The invention provides a method for desiliconizing cobalt white alloy, relating to a method for preparing electrolyzed copper and high-purity cobalt salt by taking high-silicon cobalt white alloy as raw material. The method is characterized in that the desiliconizing process sequentially comprises the following steps of: (1) melting cobalt white alloy; (2) adding a desiliconization agent for reaction; (3) then adding a slag former for slagging; (4) separating slag from melt; and (5) atomizing the separated melt into alloy powder used for recovering nickel, cobalt and copper. In the method fordesiliconizing cobalt provided by the invention, the slag former is available and is low in price; the desiliconization agent can be waste cobalt oxide, waste copper oxide, waste lithium cobaltite, crude cobaltic hydroxide and the like, thus being beneficial to comprehensive recovery of raw materials; alloy after desiliconization is directly atomized into powder; the alloy after desiliconization can stably produce alloy powder with silicon content of being less than 2%. The silicon content is less than 3%, the conventional leaching method can be adopted for recovering cobalt and copper, posttreatment is easy, operation is simple and easy, metal recovery rate is high, and application prospect is good.