As a new nano material oil displacement system，molecular deposition filming flooding agent（MDFFA）can effectively improve oil displacement efficiency. In this paper，trihydroxymethyl aminomethane，epichlorohydrin and triethylamine were selected as raw materials to synthesize a single molecular biquaternium salt system for molecular deposition film oil displacement. The viscosity，cation degree，surface tension and contact angle of MDFFA were measured，and the oil displacement effect was evaluated by dynamic flooding test. The results showed that MDFFA had stable performance，and the viscosity of the system was about 1.11 mPa·s. When the concentration was 800 mg/L，the cation degree reached up to 71.73%，and the adsorption performance on the surface of sandstone was the best. MDFFA could change the wettability of the oil-wet surface slide，the connect angle being of 98.70°，to the weak oil-wet，the connect angle being of 85.31°，and made the water-wet surface slide，the connect angle being of 58.1°，more hydrophilic，the connect angle being 45.58°. MDFFA could displace the crude oil that could not be produced by water flooding. After water flooding was converted to molecular deposition flooding，the displacement efficiency increased from 42.55% to 48.29%，while after molecular deposition flooding directly，the displacement efficiency reached up to 54.81%. Compared with molecular film flooding after water flooding，direct molecular film flooding could enhance higher oil recovery.