Longchuansmilus is an extinct genus of machairodontine (sabre-toothed) cat that lived in China during the Late Miocene.

[1] The generic name "Longchuansmilus" is refers to the Longchuan River, which runs along the Yuanmou Basin, and the Greek σμίλη/smilē meaning "dagger".

The specific name honours Xingyong Zhang, who has helped greatly in the discovery and study of the fossils at the Yuanmou hominid site.

[1] Longchuansmilus would have coexisted with proboscideans, the beaver Sinocastor, the rodent Kowalskia, the flying squirrel Pliopetaurista, the rabbit Alilepus, and the ape Lufengpithecus.

Animals found near the fossil include tapirs, insectivores, flying squirrels, bamboo rats, freshwater birds, fish, frogs, turtles, crocodiles, beavers, otters and terrestrial birds, all which point to a swampy or lacustrine environment.