Objective:To establish a method of genomic DNA extraction from whole blood using Fe3O4/Au composite particles as a carrier. Methods: Two crucial conditions （sodium chloride concentration and amount of the magnetic particles） were optimized and 8 different human whole blood samples were used to purify genomic DNA under the optimal condition. Then agarose gel electrophoresis and polymerase chain reaction （PCR） were performed. Results: The optimal binding condition was 1.5 mol/L NaCl/10% PEG

and the optimal amount of Fe3O4/Au composite particles was 600 μg. The yields of the genomic DNA from 100 μl of different whole blood samples were 2-5 μg

and the ratio of A260/A280 was in the range of 1.70-1.90. The size of genomic DNA was about 23 kb and the PCR was valid. Conclusion: The purification system using Fe3O4/Au composite microparticles has advantages in high yield

high purity

ease of operating

time saving and avoiding centrifugation. The purified sample was found to function satisfactorily in PCR amplification.