Species of the genus Hansarsia play crucial roles in marine planktonic ecosystems, but there is often confusion and misidentification. This study employed morphological analysis methods to conduct in-depth research on the specimens of the genus Hansarsia collected by the Marine Biodiversity Collections of the South China Sea, Chinese Academy of Sciences, from the South China Sea and the East Indian Ocean, aiming to clarify differences between species and resolve taxonomic confusions. Our research a) supplemented and revised the characterizations of H. tenella, H. gracilis, H. microps, and H. atlantica; b) depicted the changes in the first and second thoracic legs of the four species from juvenile to adult; c) pointed out the phenomenon of two rostrum shapes in the adult H. gracilis, and the variation in the number of setae on the propodus of the first thoracic leg; d) clarified the distinctions between H. microps and H. atlantica in the South China Sea and the Eastern Indian Ocean. The research results not only enhanced the accuracy of species identification within this genus but also provided a scientific basis for the conservation and sustainable utilization of krill resources.