Jellyfish is a common toxic zooplankton in ocean. We successfully captured a kind of jellyfish 200?m underwater in Antarctica， and identified it as a jellyfish Cyanea sp. through morphological examination and MT-CO1 phylogenetic analysis. A total of 40，468 unigenes were harvested through transcriptome sequencing. We also successfully annotated 12，955 (32.01%) unigenes with the NR database， 10，882 (26.89%) unigenes with the SWISSPROT database， 4951 (12.23%) unigenes with the GO database， and 4901 (12.11%) unigenes with the KEGG database. In the proteomic analysis， a total of 11，159 peptides and 2630 proteins were harvested using the constructed transcriptome as the database. A number of 771 (29.31%) and 841 (31.98%) proteins were annotated against the GO and KEGG database， respectively. Moreover， a number of 29 toxic proteins matched from the 145 toxin-related unigenes were successfully screened， including 6 metalloproteinases， 4 phospholipases， 2 serine proteases， 1 serine protease inhibitor， 7 toxin-related venom and 9 other toxins. Our study is the first to identify a polar jellyfish Cyanea sp. with transcriptomics and proteomics， and these data can further serve as a public database for the identification of potential polar jellyfish-derived lead compounds feasibly functioning in the cold environment. SIGNIFICANCE: With increasing discussions on marine biodiversity and global warming， polar species have gradually become a focus for research. To the best of our knowledge， there is only one paper in pubMed about the mitochondrial genome of the Antarctic stalked jellyfish Haliclystus antarcticus Pfeffer. In this study， we captured a type of jellyfish (named BD-4) from the Southern Ocean (60°29'57" S， 52°11'44"W) on the scientific expedition ship "Xue Long" at the end of 2016. Although the samples were stored and transported by the ship at only -20?°C for more than two month， we successfully extracted the total RNA， and performed molecular species identification and combined analyses of de novo transcriptomics and proteomics. In addition to conventional bioinformatics techniques such as GO and KEGG annotation， we screened and listed toxic proteins， aligned the sequences， simulated three-dimensional structures and performed molecular phylogenetic analysis for typical components， including metalloproteinase and serine proteinase. Our study is the first to identify a polar jellyfish Cyanea sp. with de novo transcriptomics and proteomics， and these data can further serve as a public database for the identification of potential polar jellyfish-derived lead compounds.