Provided is a method of solubilizing a poorly soluble/insoluble active material through formation of an oligomer composite, in which a structure having a hydrophobic cavity structure is formed by using oligomers derived from two types of hydrophilic natural polymers and a poorly soluble/insoluble component is encapsulated in the cavity structure, and thus, self-aggregation of the poorly soluble/insoluble material is prevented and simultaneously, thermodynamic stability increases to effectively solubilize the poorly soluble/insoluble material. According to the constitution of the present invention, the method may include a first operation of preparing an oligomer composite having a cavity structure formed therein by mixing and dissolving oligomers derived from two types of hydrophilic natural polymers in water, and a second operation of adding a poorly soluble/insoluble material to the oligomer composite to encapsulate the poorly soluble/insoluble material in the hydrophobic cavity structure of the oligomer composite.
