Abstract: Neighbor-joining method is one of the most effective methods based on distance data constructing phylogenetic tree.But its clustering process may neglect some more reasonable topological structure and cause low accuracy.In order to advance the accuracy of neighborjoining method, this paper proposes an improved method. The method uses neighbor-joining method to generate an initial tree, and then searches for the maximum-likelihood phylogenetic tree according to RF distance. The experiment results show that the improved method is superior to neighbor-joining method.

Key words: phylogenetic tree, neighbor-joining method, maximum likelihood, RF distance, heuristic search