[2] Echinocereus polyacanthus grows solitary or in clusters, often forming groups or cushions with up to 400 shoots.

[3] The bright to dark green cylindrical shoots taper at both the base and tip, measuring 10 to 30 centimeters in length and 2 to 7.5 cm (0.79 to 2.95 in) in diameter.

[3] Each plant has one to seven brown or yellow-brown central spines, thickened at the base, and up to 5 cm (2.0 in) long, though their length varies.

[3] The flowers are tubular to funnel-shaped, ranging from bright pinkish-orange to deep red, with a yellowish or whitish throat.

[5] The specific epithet "polyacanthus" comes from the Greek words "poly" (many) and "akantha" (thorn), referring to the species' thorny shoots.