The present invention relates to a process for preparing post-crosslinked polymer bead with increased surface area and pore volume, and suitable pore size, allowing the separation of organic compounds by post-crosslinking gel-type copolymer bead whose crosslinking degree is low and initial surface area is small, or macroporous-type copolymer bead whose crosslinking degree is high and initial surface area is intermediate in the presence of a Friedel-Crafts catalyst, and polymer beads produced thereby. Though the surface area and pore volume of polymer beads may be varied depending on physical properties of copolymer beads and Friedel-Crafts reaction conditions, the present invention provides polymer beads with larger surface area than that of commercially available polymeric adsorbents produced by the conventional method employing a porogen only. Further, the polymer beads may be used as polymeric adsorbent and catalyst carrier, since they exhibit a high adsorption capacity for organic compounds in an aqueous solution, and chemically modified ones may be employed as polymer carrier, ion-exchange resin, and chelate resin.