Squirrel snakes can weigh up to 500-600g.

The body of the squirrel snake is slightly slender, with a body length of 1.5 to 2 meters. The squirrel snake has an oblong head, large eyes and round pupils. The body scales of the gray rat snake are smooth, with a few rows of ribs in the center of the back of the body, the head and the back of the body are brown-gray  color, the center of each scale is gray-black or black-brown, the edge is dark brown, and the front part of the body is dark brown. The blue-brown vertical lines are formed by connecting the blue-brown in the middle of each scale.

The back of the squirrel snake is black with a fine mesh pattern. The upper lip and ventral scales are pale yellow, the sides of each scale are blue-grey, and the tail is dark brown.