Graphitic carbon nitride nanorods/titanium dioxide microspheres (g-C3N4 NRs/TiO2 MSs) Z-scheme heterojunctions were simply prepared by a one-step hydrothermal method, which showed improved visible-light-induced photocatalytic activity for the degradation of tetracycline hydrochloride (TC-HCl). The photodegradation activity of g-C3N4 NRs/TiO2 MSs is 6.6 and 1.9 times better than that of pristine g-C3N4 and TiO2, which is assigned to the unique morphology and formed heterojunction. Hydroxyl radical (⋅OH) and superoxide radical (⋅O2−) were the main species for TC-HCl photodegradation according to capture experiments, and a possible mechanism is proposed. This study provides an effective reference for the preparation of binary heterostructures with excellent photocatalytic activity from a simplified process.