Protein-protein　complex,　composed　of　hydrophobic　and　hydrophilic　residues,　can　be　divided　into　hydrophobic　and　hydrophilic　amino　acid　network　structures　respectively.　In　this　paper,　we　are　interested　in　analyzing　these　two　different　types　of　networks　and　find　that　these　networks　are　of　small-world　properties.　Due　to　the　characteristic　complementarity　of　the　complex　interfaces,　protein-protein　docking　can　be　viewed　as　a　particular　network　rewiring.　These　networks　of　correct　docked　complex　conformations　have　much　more　increase　of　the　degree　values　and　decay　of　the　clustering　coefficients　than　those　of　the　incorrect　ones.　Therefore,　two　scoring　terms　based　on　the　network　parameters　are　proposed,　in　which　the　geometric　complementarity,　hydrophobic-hydrophobic　and　polar-polar　interactions　are　taken　into　account.　Compared　with　a　two-term　energy　function,　a　simple　scoring　function　HPNet　which　includes　the　two　network-based　scoring　terms　shows　advantages　in　two　aspects,　not　relying　on　energy　considerations　and　better　discrimination.　Furthermore,　combing　the　network-based　scoring　terms　with　some　other　energy　terms,　a　new　multi-term　scoring　function　HPNet-combine　can　also　make　some　improvements　to　the　scoring　function　of　RosettaDock.　(c)　2008　Elsevier　B.V.　All　rights　reserved.