Abstract: Mycosporine-like aminoacids (MAAs) exist in cyanobacteria, fungi, and eukaryotic micro-and macro-algae. They absorb ultraviolet (UV) and hence protect these organisms from the damages caused by the environmental UV radiation. The understanding of the biosynthetic pathway and the genetic properties of MAAs is fundamental for the fast-detection of MAAs genes. In the present study, we amplified the partial coding sequence of the gene encoding DHQS enzyme in Dolichospermum flos-aquae CHAB1629 that was isolated from the Taihu Lake. The nucleotide similarity between D. flos-aquae CHAB1629 and Anabaena sp. 90 was 99%, and it was only 53.6% between D. flos-aquae CHAB1629 and Anabaena variabilis ATCC 29413. High-performance liquid chromatography (HPLC) assays confirmed that MAAs in D. flos-aquae CHAB1629 were shinorine.