In order to improve the solubility of Betaine surfactant in the high-temperature and high-salinity reservoir conditions of Shengli oilfield，the hydroxyl groups were introduced onto the molecular chains of sulfobetaine surfactant，a novel alkyl-hydroxyl-sulfobetaine surfactant MBS16 was synthesized by two-step method. The structure of the surfactant MBS16 was characterized by infrared spectrum （IR） and nuclear magnetic resonance （NMR）. The oil/water interfacial activity and foam properties were investigated using spinning-drop interfacial tensiometer and Ross-Miles meter；and the oil displacement experiment was conducted in a sandpacked core with the permeability of 1500 ×10^-3 μm². The results showed that interfacial tension（IFT） between 0.3% modified betaine surfactant solutions and Shengli crude oil from various blocks could reach ultralow，implying that the surfactant was temperature-resistant and salt-tolerant. Compared with single HPAM system（0.15% HPAM），the viscosity of the compound system（0.3% MBS16 + 0.15% HPAM）increased slightly. The oil displacement experiment results indicated that the compound system（surfactant/polymer）increased oil recovery by 9.4% than single HPAM system did. Moreover，the foaming ability of the modified betaine was strong and the foam stability of the modified betaine compounded with anionic-nonionic surfactant B4 was good.