The effect of surfactant on micro-cracks and fine tunnels could increase the yield of single well. The anionic-nonionic surfactant AN211 was synthesized by alkyl alcohol polyoxyethylene ether and maleic anhydride. The structure of the product was characterized by NMR. The critical micelle concentration，oil-water interfacial tension，wettability，imbibition efficiency and other properties of AN211 were studied. The results showed that the critical micelle concentration of AN211 was 0.052 g/L. The interfacial tension of AN211 solution decreased with the increase of concentration. The interfacial tension of 0.3% AN211 solution was 3.37 mN/m. AN211 had strong ability to change core wettability and short wettability time. By reducing Zeta potential on core surface，AN211 could change core wettability and achieve wettability reversal. AN211 effectively stripped oily adsorbate on core surface，and the imbibition efficiency improved with 48%. Its permeability was less affected by the degree of mineralization，and its application of water scope was wide. The performance of AN211 was better than that of amphoteric surfactant coconut oil amides acrylamide hydroxy sulfonyl betaine，cationic surfactant cetyltrimethyl ammonium chloride and oil displacement agent QY-1，which could be used for oil displacement of unconventional oil and gas reservoir.