In this study, catechin-functionalized Fe3O4-Ag nanocomposites were synthesized by a hydrothermal method. The obtained nanocomposites were characterized by TEM, SEM, AFM, XPS, XRD, FTIR and physical property measurement system (PPMS). TEM images indicated that catechin-functionalized Fe3O4-Ag nanocomposites have a spherical morphology with an average size of 25.7 nm. The SEM and AFM imaging revealed that the nanocomposites appear as a number of large particles with average diameter of 581nm. XPS and XRD and FTIR measurement confirmed the presence of catechin components, Fe3O4 and Ag in the nanocomposites. Taken together, weconclude that the catechin-Fe3O4-Ag nanocomposites in this study have a jujube cake structure in which the Fe3O4-Ag alloy nanoparticles serve as the jujube and the condensed catechin form into the cake substrate. The antimicrobial test indicated the catechin-functionalized Fe3O4-Ag nanocomposites have obvious inhibitory effects on E. coli, S. aureus, and C. albicans.