Based on ZnCo2O4 microspheres，g-C3N4/ZnCo2O4 composite were prepared by solution adsorption and insulation at 100 ℃ for 12 h. The materials were characterized by XRD, SEM, XPS and Uv-DRS. The heterostructure was formed between ZnCo2O4 and g-C3N4. The bandgap width of g-C3N4/ZnCo2O4 composite was 1.73 eV. Under the visible light irradiation, the photogenic electron (e‒) and the photogenic hole (h+) of ZnCo2O4 was effectively separated via capturing e‒ of ZnCo2O4 by the delocalized π bond of C3N4 in the heterojunction region. The photogenic h+ of ZnCo2O4 participate in reaction of the photocatalytic degradation tetracycline (C22H24N2O8, Initial concentration: 10 mg/L) in water, g-C3N4/ZnCo2O4 composite have better degradation properties for tetracycline, and the highest degradation rate is 90.02 %.