Herein, we design and synthesize a novel hydrolase model by integrating the supramolecular self-assembly of an amphiphilic short peptide (Fmoc-FFH) and electrostatic complexation (with PEI) at an aqueous liquid–liquid interface to synthesize stable peptide–polymer Fmoc-FFH/PEI hybrid capsules (FPCs). After treatment with glutaraldehyde as a crosslinking agent, we can obtain novel Fmoc-FFH/PEI/GA hybrid capsules (FPGCs). The FPGCs with imidazolyl groups as the catalytic centers exhibit high catalytic activity for the hydrolysis of p-nitrophenyl acetate (PNPA). The resulting hydrolase model (FPCs or FPGCs) shows kinetics behavior typical of natural enzymes, and the catalytic activity is higher than that of a Fmoc-FFH hydrogel. The enhanced catalytic activity may be attributed to the high density of catalytic sites on the inner surface of the hybrid capsule. Additionally, the FPGCs retained 93% of their productivity after fifteen cycles, suggesting high stability and excellent recyclability. This novel hybrid capsule is expected to be applied as a substitute for natural hydrolases in industrial production applications.