Flower-like TiO2 @MoS2 nanocomposite with a hierarchical and core@shell structure was synthesized using a two-step hydrothermal method, in which the flower-like Ti-containing precursor backbone was initially prepared to provide a large surface to enable the MoS2 sheets to coat on TiO2 uniformly. The glucose and acetate ion (Ac-1) were found to play a crucial role in the formation of the intimate interface between TiO2 and MoS2. The hierarchical composite was dispersed in silicone oil as ER fluids at 10 wt %, which exhibited a high ER efficiency by combining the advantages of TiO2 hierarchical structures and suitable conductivity of MoS2 sheets. The high polarization strength and suitable dielectric relaxation of ER fluid was obtained under electric fields, which leaded to the improvement of interfacial polarization and ER activity.