Disclosed are a core-shell structure composite carrier based on poly(vinyl alcohol) (PVA) and alginate, which has excellent physical properties by using PVA and alginate and is applicable to various hydrotreatment process by immobilizing a specific reactant to each of the core region and shell region depending on the material to be treated, and a method for preparing the same. The core-shell structure composite carrier based on PVA and alginate includes beads of a core region and beads of a shell region formed on the surface of the beads of a core region, wherein a first reactant carrying out a first unit reaction is immobilized to the beads of a shell region, a second reactant carrying out a second unit reaction is immobilized to the beads of a core region, the first unit reaction and the second unit reaction are independent from each other and are time series continuous reactions, and the beads of a core region and the beads of a shell region include PVA and alginate.
