Eucalyptus preissiana is a mallee that typically grows to a height of 3–5 m (9.8–16.4 ft) with a sprawling habit, and forms a lignotuber. It has smooth, greyish and brown bark. Young plants and coppice regrowth have stems that are square in cross-section and elliptical to egg-shaped leaves that are the greyish green, 50–93 mm (2.0–3.7 in) long, 30–62 mm (1.2–2.4 in) wide and arranged in opposite pairs. Adult leaves are sometimes arranged alternately, the same shade of dull greyish green on both sides, elliptical to egg-shaped or oblong, 65–130 mm (2.6–5.1 in) long and 25–50 mm (0.98–1.97 in) wide on a petiole 10–40 mm (0.39–1.57 in) long. The flower buds are arranged in leaf axils on a flattened, unbranched peduncle 8–25 mm (0.31–0.98 in) long, the individual buds on pedicels 2–5 mm (0.079–0.197 in) long. Mature buds are oval, 15–26 mm (0.59–1.02 in) long and 13–18 mm (0.51–0.71 in) wide with a conical to rounded operculum. Flowering occurs from September to November and the flowers are yellow. The fruit is a woody, cup-shaped, conical or bell-shaped capsule 15–27 mm (0.59–1.06 in) long and 20–38 mm (0.79–1.50 in) wide with lobes between the valves.