Protosalanx chinensis is a suitable particular species for genetic studies on nearly scaleless skin, transparency and high sensitivity to hypoxia stress. Here, we generated a high-quality chromosome-level de novo assembly of P. chinensis. The final de novo assembly yielded 379.47 Mb with 28 pseudo-chromosomes and a scaffold N50 length of 14.52 Mb. In total, 21,074 protein-coding genes were predicted. P. chinensis, Esox lucius and Hypomesus transpacificus had formed a clade, which diverged about 115.5 million years ago. In the air exposure stress experiment, we found that some genes play an essential role during P. chinensis hypoxia, such as bhlh, Cry1, Clock, Arntl and Rorb in the circadian rhythm pathway. These genomic data offer a crucial foundation for P. chinensis ecology and adaptation studies, as well as a deeper understanding of the response to air exposure stress.