The present invention provides a method for preparing a core-shell structured particle, the method using a continuous Couette-Taylor crystallizer in which a core reactant inlet, a shell reactant inlet, and a product outlet are sequentially formed on an outer cylinder along a flow direction of a fluid flowing in a Couette-Taylor fluid passage between the outer cylinder and an inner cylinder, wherein a core particle is primarily formed in the fluid passage by a core reactant supplied through the core reactant inlet; a shell layer is formed on a surface of the core particle to cover the core particle by a shell reactant supplied through the shell reactant inlet; and a core-shell structured particle in which the shell layer is formed on the circumference of the core particle, is discharged to the outside through the product outlet.