Protein-protein interaction (PPI) regulates many fundamental cellular processes and a key step in understanding the function of a protein-coding gene is to identify potential interacting partners. Although high-throughput methods already provide a large amount of data, unfortunately they are time-consuming and tend to be very expensive. The co-evolution model is based on a concrete biological hypothesis, namely interacting proteins evolve in coordination. The goal of our work is to test the validity and extent of this hypothesis and to determine how successful it is in discerning interacting from non-interacting proteins. We use evolutionary information from orthology proteins between human and other vertebrates to construct a co-evolution model. A de novo, flexible, and computational un-expensive PPIs-prediction method is proposed in our work.