SELEX(systematic evolution of ligands by exponential enrichment)is a new combinatorial chemistry technology.An 81 nucleotides ssDNA pool containing 35 random nucleotides flanked by invariant primer was designed.The PCR amplification conditions were optimized for converting the ssDAN pool into dsDAN pool. Compared to asymmetry PCR,the technique based on biotin-streptavidin-magnetism bead was suitable forgeneration of ssDAN from dsDAN.Since the hydrophobicity of deoxyribose leads to an inherently higher degree of background binding to nitrocellulose filters,panning procedures on microtiter plates were employed.After 9 rounds selection,the percentage of the ssDAN pool bound to HCV core protein inceased from 0.5% to 32.5%.