[1] Haikoucaris measured about 38 mm in body length.

[1] The elongated body compose of a semicircular head shield, 13 trunk tergites and presumely a short, spine-like telson.

[2] Each of the trunk segment possess a pair of biramus appendages that each comprising a leaf-shaped exopod and a possibly 7-segmented endopod.

[2] Haikoucaris may have been a predator, with its great appendages and exopod suggested to be used for hunting and swimming respectively.

[2] Within megacheirans, Haikoucaris is generally accepted to be a member of the clade Cheiromorpha alongside Yohoia and Leanchoiliidae.