Banksia biterax is a dense, rounded, bushy shrub that typically grows to a height of and has hairy stems but does not form a lignotuber. Its leaves are linear in outline, long and on a petiole up to long. The leaves are serrated to the midvein, with 60 to 110 triangular lobes and are woolly-hairy on the lowersurface. The flower spikes are borne on short side branches and have between 150 and 200 pale to dark brown flowers each with a perianth long and a cream-coloured pistil long. Flowering occurs from May or July to October and the fruit is an egg-shapedfollicle about long.