Diuris alba is a
tuberous,
perennial herb, usually growing to a height of . There are up to three linear leaves arising from the base of the plant, each leaf long, wide and rolled so that the sides of the leaf face each other. There are between two and seven white flowers with lilac or purple markings arranged on a flowering stem, each flower about wide. The
dorsal sepal is egg-shaped, long and wide with its margins turned downwards. The
lateral sepals are linear to lance-shaped, long, wide and turned downwards, either parallel to each other or crossed. The
petals are erect, ear-like above the flower, long and wide with a dark-coloured, stalk-like "claw" long. The
labellum is long and has three lobes. The central lobe is a broad egg shape to almost circular, wide with a raised midline. The
lateral lobes are linear to lance-shaped with the narrower end towards the base, long and wide. There are two broad
calli long. Flowering occurs from August to November. ==Taxonomy and naming==