The maximum weight of the Hainan flash-scale snake is 3kg.

The male body length of the Hainan Amphora snake is 865mm, and the female body length of the Hainan Amphora snake is 610mm. The tail length accounts for about 0.075 of the total length.

The back of the Hainan flash-scale snake is blue-brown with metallic luster. There are 1 or 2 intermittent white longitudinal stripes between the bottom 3 rows of dorsal scales on both sides, the bottom row of dorsal scales is gray-white; ventral surface is gray-white, and the lower tail scales at the rear of the tail are blue-brown. The back of the head is blue-brown, and the head and belly are light blue-gray or light brown. The head is small and slightly flat, the muzzle is round and pure, and the trunk is cylindrical.