AbstractReconstruction of the evolutionary history of species based on the genetic and species diversity is one of the most important subjects in the current study of molecular evolution. If reliable phylogenies are produced , they will shed light on the sequence of evolutionary events , and help us to understand the mechanisms of evolution as well as the history of organisms. The goal in this paper is to give a brief introduction to several important issue in phylogeny inferring : the tree-building methods , data transformation , reliability of inferred tree , and several common used computer programs.