Peptide assembly has reached exquisite levels of efficiency in the creation of bioactive materials. However, we have not yet been able to take what we have learned from peptide assembly to develop a general strategy for the fabrication of biomimetic underwater adhesives, which retain significant advantages as medical glue for clinical treatment. Herein we report a simple approach to prepare peptide-based adhesives through the supramolecular polymerization of cationic peptides drove by polyoxometalates (PMs). Mass spectra, Fourier-transform infrared spectra and W-183 NMR spectra confirmed the structural integrity of peptides and PMs during the coassembly process. Scanning electron microscopy demonstrated that the multivalent interactions between peptides and polyoxometaltes led to the formation of robust 3D network structures. The rheological study revealed that the peptide/PM assemblies exhibited mechanically rigid gel-like behavior and self healing property. Interestingly, the assemblies showed the capacity to adhere various wet solid materials under waterline. The shear strength of the peptide-based adhesives are stronger than that of the commercially available fibrin glue. This finding is exciting and serves to expand our capability of the fabrication of peptide-based materials.