The study of evolutionary relationships among organisms is vital in evolutionary biology. To reconstruct a reliable species phylogeny, one of the most important issues is to choose proper molecular markers and take full advantage of phylogenetic information contained in these markers. Intra-individual allele heterozygotes (IIAHs) have been commonly detected in intron phylogenetic studies. How to incorporate IIAHs into phylogenetic framework has been a focus in current studies. In this review, the conception, isolation, and analytic methods of IIAHs in phylogeny were summarized.