Abstract: For inquiring into the genteic diversity and genetic structure of black porgy Acanthopagrus schlegeli, We used polymerase chain reaction (PCR) and direct nucleotide sequencing to analyze the 547~549 bp 5′end of the D-loop region from 72 A.schlegeli samples, which captured from Beihai(Guangxi province), Shenzhen(Guangdong province) and Qingdao(Shandong province). The results show that the A, T, G and C mean contents in those fragments were 30.8%, 21.8%, 36.3%, 11.0%, respectively. There were 55 variable nucleotide positions in those gene fragments, which included 38 transition sites and 13 transvertion sites, 1 insert/ transvertion site and 3 deletion/trasvertion. Comparisons of these 72 partial D-loop sequences revealed 51 mitochondrial haplotypes in A.schlegeli, the haplotype rate was 70.8%. Those indicated that there were rich nucleotide variational polymorphism exited in A.schlegeli. Phylogenetic trees of haplotypes were constructed by NJ method. Neither significant genealogical branches nor geographic cluster were found. It showed that mitochondrial DNA highly variable region sequence is unsuitable to be used as a genetic marker for population identification.