The large-headed snake is a medium-sized snake with a total length of 810-1500 mm. The head is large and the neck is thin, and the head and neck are clearly distinguished; the eyes are large and the pupils are oval.

The back of the large-headed snake is brown, brown-grey or russet, and the midline of the back is decorated with large black or black-brown spots , There are staggered rows of small spots on both sides of the large spot; the ventral surface is dark white or yellowish brown, decorated with irregular markings. There are short black longitudinal stripes from the tip of the snout to the back edge of the forehead scales, and brown stripes from the back of the eyes to the corners of the mouth.