Abstract: Pointiong at the problems of high water injection、serious under injection、short term of validity of common acid in low permeability oil reservoir of Nanpu oil field. It is applied the on-line injection well stimulation technology of quaternary binary surfactant. It is indicated that the interfacial tension of crude oil can reach 10-2-10-3mN/m. It can change the rock strong water wet into weak water wet. and can prevent clay swelling. The experiments showed that the water drive depressurization rate can reach above 30%. The field application results of 24 wells showed that the field implementation efficiency was 94%, the initial injection pressure of water injection wells decreased by 9.5 MPa on average, the validity period was 200d, and the average enhanced injection of single well was more than 2×103 m3, which improved the water injection problem of Nanpu oil field low permeability reservoir.