N-K2Ti4O9/UiO-66-NH2 composites synthesized by a facile solvothermal method have a core-shell structure with UiO-66-NH2 forming the shell around a N-K2Ti4O9 core. Their photocatalytic activities in the degradation of dyes under visible light irradiation were investigated. The N-K2Ti4O9/ UiO-66-NH2 composites exhibited higher photocatalytic activity than the pure components. This synergistic effect was due to the high adsorption capacity of UiO-66-NH2 and that the two components together induced an enhanced separation efficiency of photogenerated electron-hole pairs. The mass ratio of N-K2Ti4O9 to ZrCl4 of 3:7 in the composite exhibited the highest photocatalytic activity. Due to the electrostatic attraction between the negatively charged backbone of UiO-66-NH2 with the positively charged groups of cationic dyes, the composites were more photocatalytically active for cationic dyes than for anionic dyes.