Odorrana hosii inhabits lowland and hillside primary and secondary forests at elevations below approximately 750 m a.s.l. It is closely associated with rocky streams and is never found far from them.

Males typically measure 50–68 mm in snout–vent length, while females may occasionally reach up to 100 mm. The hindlimbs are strong and elongated. The fingers and toes bear relatively large, grooved discs that aid in climbing. This species can potentially be confused with Hylarana raniceps and Hylarana megalonesa due to its green dorsal coloration and white upper lip. However, Odorrana hosii is larger and more robust, possesses larger adhesive discs, and has distinct dark cross-bars on the limbs.

The skin secretions of this frog are highly toxic and can kill other frogs upon excessive contact. After handling, it is essential to wash your hands thoroughly. Avoid any contact of the secretions with your eyes, mouth, nose, or open wounds.

The dorsal surface is green, while the flanks and legs may be either green or brown. The upper lip is white to cream-colored and extends as a streak toward the region above the forelimb insertion. The limbs bear dark cross-bars. The chest and belly are white, and the eardrum is clearly visible.

This frog is commonly observed at night, perching 1–2 m above ground on shrubs near medium to large rocky streams, or on vegetation overhanging the riverbank. Due to its size, it is capable of preying on smaller frogs and has been observed doing so.

The tadpoles are dark gray in coloration. The tail fin is moderately high and the tail itself is long. The fin lacks any skin glands. The iris is golden (not red), a feature that distinguishes them from the superficially similar tadpoles of Hylarana signata and H. picturata, which may occur in the same microhabitats. Tadpoles of O. hosii are usually found in quiet side-pools of rocky streams, typically deeper than 50 cm, with thick accumulations of leaf litter and plant debris at the bottom.