Allele frequencies for 15 short tandem repeat (STR) loci were obtained from a Chinese Han population in Henan province of middle China. No deviation from Hardy-Weinberg equilibrium was observed for the STR loci except for D3S1358. The 15 STR loci are potentially useful for paternity testing and forensic casework in the Henan population. A phylogenetic tree based on CODIS STR allele frequencies of 25 Han populations revealed noticeable but far less clear distinctions between southern and northern Chinese populations; the Henan Han population was located at an intermediate position between south and north Chinese Han populations, relatively closer to Chaoshan and Minnan Han. Moreover, admixture analysis showed a large proportion of Central Plains Han origin in Chaoshanese and Minnanese. Admixture and phylogenetic analysis also reflected the genetic similarity shared by these two groups.