Abstract: A brief review is given on problems of species conceps in cladistics and evolutionary systematics, and some advances in the study on species problem are introduced. Particularly Nixon and Wheeler's phylogenetic species concept and two procedures of delimitating phylogenetic species— Davis and Nixon's population aggregation analysis and Brower's cladistic haplotype aggregation arereviewed in detail.

Key words: Cladistics, Species problem, Phylogenetic species, Population aggregation analysis, Cladistic haplotype aggregation