The present disclosure relates to a method for size-selective separation of 2-dimensional plate particles using spherical particles. Since the separation method of 2-dimensional plate particles according to the present disclosure is simple, economical and extensible to large-scale applications, it can contribute greatly to commercialization of plate particles by reducing cost and preventing deterioration of physical properties. The 2-dimensional plate particles having uniform size can be useful in such applications as transparent electrodes, solar cells, composites, drug delivery, biosensors, etc.