Trees to 25 m tall, d.b.h. to 40 cm. Bark gray. Branches pubescent when young, glabrescent. Petiole 5-8 mm, transversely rugosely striate, puberulent; leaf blade oblong to oblong-elliptic, 8-20 × 3.5-8 cm, thinly leathery to leathery, glabrous, adaxially shiny, secondary veins 14-18 on each side of midvein, parallel, ascending to margin, and adaxially conspicuous, base broadly cuneate to rounded, apex acuminate. Inflorescences axillary or on old branches, several flowered. Pedicel 1.5-3 cm, puberulent; bracteoles at base of pedicel, broadly ovate. Sepals broadly ovate, ca. 5 × 5 mm, outside puberulent, inside glabrous, apex obtuse to acute. Petals yellowish, oblong-ovate to ovate-lanceolate, 2-3.5 × 1-1.5 cm, outside puberulent or glabrous, inside glabrous; inner petals slightly longer than outer petals. Stamens cuneate; connectives apically obtuse. Carpels many, oblong, densely pubescent; ovule 1 per carpel, basal; stigmas capitate. Fruiting pedicel 3.5-4 cm; monocarp stipes 2.5-5 cm; monocarps red, ovoid-ellipsoid, 2.5-5 × 1-2 cm, glabrous, apex obtuse. Seed 1 per monocarp. Fl. Apr-Jul, fr. Oct-Dec.

The wood of Polyalthia laui is used for making household implements and as structural timber.

Evergreen broad-leaved forests on slopes; 300-700 m. Hainan [Vietnam].