A highly stable and strongly fluorescent metal-organic gel, Zr-TCBPE-MOG, was successfully synthesized through the combination of aggregation-induced emission luminogens (AIEgens) 1, 1, 2, 2-tetra(4-carboxylbiphenyl) ethylene (H4TCBPE) with Zr (IV) cations. The fluorescence of Zr-TCBPE-MOG exhibits a sensitive response to piceatannol (3,3',4,5'-tetrahydroxy trans-stilbene, PCT), whereas its structural analogues, such as resveratrol, pterostilbene, rhapontigenin, and pinosylvin, which share the same core skeleton, have no effect on it. Therefore, Zr-TCBPE-MOG can function as a fluorescent probe for rapid differentiation and detection of PCT among these structural analogues. A simple and rapid fluorescence method was established via the selective fluorescence quenching effect of PCT on Zr-TCBPE-MOG through the photoinduced electron transfer effect. Under optimal measurement conditions, the proposed method achieves high sensitivity for PCT with a linear detection concentration range from 3.5 to 250 nM and a low detection limit of 2.8 nM. It also can realize selective determination of PCT in serum samples. This work reveals the great potential of MOG for the rapid and highly specific differentiation of structurally similar drugs.