Silver phosphate (Ag₃PO₄) is a promising photocatalyst, but the photo-corrosion issue limits an effective and comprehensive photocatalysis degradation of tetracycline (TC). In this work, a unique graphitic carbon nitride-Ag₃PO₄ (KCN-AP_{(40 %)}) core-shell structure was prepared via a simple chemical sedimentation method. The unique graphitic carbon nitride sheet encloses Ag₃PO₄ to trap excited electrons from the conduction band position of Ag₃PO₄, suppressing the reduction of Ag⁺ and Ag metal deposition on the surface of Ag₃PO₄. Under visible light irradiation, the optimized KCN-AP_{(40 %)} can photodegrade nearby 100 % of TC within 20 min with a first-order kinetic constant of 0.127 min^−1, which is 3.34 and 3.97-folds higher than those of Ag₃PO₄ and graphitic carbon nitride, respectively. A series of factors that may affect photoactivity of KCN-AP _{(40 %)} including pH, inorganic ions, and organic matter are investigated. In final, the photodegradation mechanisms and intermediates were proposed based on ex-situ HPLC-MS. This work explains the deep decomposition of TC and presents a facile approach for designing and manufacturing Ag₃PO₄ based nanohybrids.