The great success in de novo protein design indicates the coming of a new protein engineering era.Many progresses in structure design have been made.One of the challenges was to understand the interactions between protein-protein and protein-solvent.Although we had good examples of protein function design based on natural protein structures, forde novo protein design, the stability of small protein is usually not as robust as nature proteins.Though good hydrophobic core often is considered in the first place, slight mutation often leads to the breakdown of the whole structure.A commonly occurring super-secondary structure motif, the βαβ-motif, was de novo designed in our previous work.The 36 amino acids peptide exists as a monomer in aqueous solution.We successfully got a stable dimer of the protein by introducing a few additional mutations.Circular dichroism spectrum (CD), gel filtration, Sedimentation equilibrium (SE) and nuclear magnetic resonance (NMR) were used to study the structure of the small protein.The monomer structure of the protein was solved by 2D-NMR.The dimer model was built based on possible NOE signals between the two monomers using the program HADDOCK1.This dimmer protein may provide a framework for de novo enzyme design.