Cyanothamnus acanthocladus is a shrub that grows to a height of about with spreading branches and spiny branchlets. Its leaves are narrow egg-shaped with the narrower end towards the base, long and often clustered on the older wood. The flowers are white and are borne on the ends of short shoots on a pedicel long. The four sepals are narrow triangular, fleshy, glabrous and about long. The four petals are elliptic and about long and the eightstamens are hairy. Flowering occurs in September.