Abstract: The present application relates to a method for preparing olefin-based segmented copolymers through reversible addition-fragmentation chain transfer (RAFT), wherein the method comprises: a step of polymerizing vinyl-based monomers through reversible addition-fragmentation chain transfer (RAFT) using a trithiocarbonate-based chain transfer agent to synthesize vinyl-based polymers; and a step of grafting the synthesized vinyl-based polymers to olefin-based polymers. The method of the present invention successfully synthesizes olefin-based segmented copolymers through the two simple above-described steps.