Antibiotic drugs have become the important organic pollutants in the water resources, the high-efficient removal of which is one of the foremost works for protecting water environment. The new Z-scheme mes-Sn3O4/g-C3N4 heterostructure was obtained in present work, compared with single g-C3N4, which exhibits more superior photocatalytic performance for degrading and mineralizing tetracycline hydrochloride in water. The investigations of microstructure, physical properities and photoelectrochemical behaviors indicate that the modification effect mesoporous Sn3O4 on the surface of g-C3N4 nanosheets fabricates close heterostructure, which enlarges distinctly the specific surface area and improves dramatically the separation efficiency of charge carriers. Furthermore, the possible photocatalytic reaction mechanisms including transfer behaviors of charge carriers, generation of reactive species, degradation intermediate products of TC-HCl are also revealed in depth.