Iron tetranitro-phthalocyanine was synthesized by the reaction of 4-nitrophthalimide with FeCl₃, and was then modified by γ-(trimethoxysilyl)propane-1-thiol to prepare functionalized iron phthalocyanine. A graphene oxide/iron phthalocyanine composite was then prepared, comprising functionalized iron phthalocyanine supported on the surface of graphene oxide via covalent bonds. All these complexes were characterized by infrared spectra (IR), X-ray diffraction, ultraviolet/visible (UV/vis) and Raman spectroscopy, and scanning electron microscopy. The catalytic properties of the graphene oxide/iron phthalocyanine composite for catalyzing adrenaline oxidation were evaluated by measuring the absorbance intensity at the characteristic peak of the oxidation product. A fiberoptic adrenaline sensor based on a graphene oxide/iron phthalocyanine composite catalyst and fluorescence quenching was fabricated and studied. The relationship between the concentrations of dissolved oxygen and adrenaline was investigated by measuring the phase delay φ. The results showed that the graphene oxide/iron phthalocyanine composite can effectively catalyze adrenaline oxidization, and the optimal conditions are pH = 8.0, T = 30 °C, and mGO-FePc = 4.0 mg/mL; moreover, concentrations of adrenaline can be detected in the range from 1.8×10-6 to 9.2×10-5 mol/L with a sensor response time of 4 min.