Living graft macromolecule has been prepared through reversible addition-fragmentation chain transfer (RAFT) living radical polymerization in one step. Then, it was used to make polymer-dispersed liquid crystal (PDLC) by controlling the mole ratio of styrene (St) to 1,6-hexanediol diacrylate (HDDA) and adjusting the content of prepared graft macromolecule. The results showed that electro-optical properties of PDLC have been optimized. Different concentration of living graft macromolecule and different mole ratio of St/HDDA led to substantial improvement of driving voltage (threshold voltage and saturation voltage) and memory effect of PDLC simultaneously. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012