Fluoroquinolones (FQs) antibiotic residues threaten ecosystems and human health, necessitating rapid on-site monitoring tools. We synthesized a bimetallic Fe-Cu nanozyme using a Fe-MIL-100 self-sacrificing template via hydrothermal treatment and calcination. This nanozyme exhibited FQs-enhanced peroxidase-like activity, enabling a smartphone-based colorimetric platform for detecting enrofloxacin (ENR), ciprofloxacin (CIP), norfloxacin (NOR), and ofloxacin (OFL). The detection relies on antibiotic-enhanced catalytic oxidation of 3,3',5,5'-tetramethylbenzidine (TMB), producing color changes quantified by smartphone RGB (red-green-blue) analysis. The quantitative performance of the method was evaluated for four target FQs. It exhibited wide linear ranges with limits of quantification (LOQs): for ENR, 0.1-100 μg mL-1 with an LOQ of 0.1 μg mL-1; for CIP, 5.0-200 μg mL-1 with an LOQ of 5.0 μg mL-1; for NOR, 1.0-125.0 μg mL-1 with an LOQ of 1.0 μg mL-1; and for OFL, 1.0-200.0 μg mL-1 with an LOQ of 1.0 μg mL-1. Results correlated well with microplate reader data and demonstrated reliability in natural water and meat samples. Mechanistically, the nanozyme exhibits dramatically enhanced catalytic efficiency, with Km value for H2O2 (0.566 mM), which is 6.54-fold lower than that of horseradish peroxidase (HRP). Furthermore, ENR acts as an efficient activity booster, reducing the Km for H2O2 to 0.336 mM (11-fold lower than that of HRP) and increasing Vm values for H2O2 and TMB (3.95 × 10 -7 M s -1, 4.87 × 10 -7 M s -1, respectively) being 4.54-and 4.87-fold greater than those of HRP. This work elucidates the antibiotic-nanozyme synergistic mechanism and provides a portable, cost-effective sensing strategy for environmental and food safety applications.