Abstract: The binding of human DNA polymerase β to DNA template-primer duplex and single-stranded DNA have been studied by using surface plasmon resonance biosensor.In this study,it is shown that two polymerase β inhibitors（nervonic acid and linoleic acid） prevented the binding of polymerase β to the single strand overhang and changed the binding of polymerase β to DNA duplex from a parallel binding mode to a single binding mode.The affinity of polymerase β to the template-primer duplex region was decreased by 20 and 5 times in the presence of nervonic acid and linoleic acid,respectively,as compared to that in the absence of inhibitors.The inhibitory effect of nervonic acid on DNA binding of polymerase β seemed to be more significant than linoleic acid.Based on the effects of fatty acids on the DNA binding affinity of polymerase,the mechanism of DNA-polymerase interaction in the presence of polymerase β inhibitors is extensively understood.The results obtained from the biosensor technique may provide additional information on the design of anticancer and antiviral drugs.