Peptide-oligonucleotide conjugates were synthesized using two strategies: a mimetic signal peptide-conjugated oligonucleotide was assembled stepwise on CPG by using 2,2-dimethyl-3-hydroxypropionic acid as a linker. To solve the precipitation problem in the coupling reaction caused by the electrostatic interaction of arginine-rich peptides and oligonucleotide, oligonucleotides were absorbed on an anion-exchange resin, and then the on-resin fragment was applied for the conjugation with arginine-rich peptide. The peptide-antisense oligonucleotides showed permeability to the cell membrane of HepG-2 cells.