The average length of an adult green tree python is about 90 to 120 centimeters, with a record of 213 centimeters. The position of their upper lip scales has a pair of heat-resistant grooves. Its body color is bright green, with a blue stripe along its spine and scattered white or yellow scales all over its body. There are also green tree pythons in some origins that only have lines composed of yellow and white scales in the center of the back.

Larval green tree pythons mainly come in pale yellow, bright red and brick red colors. The pale yellow individuals have mainly black stripes on the back, mixed with white spots; the bright red and brick red individuals have mainly white back stripes with black spots on the back. Green tree python larvae hatched in the same litter may appear in various colors at the same time. The juvenile green tree python generally changes to the green tone of the adult as the main color within a few months to a few years after birth. Green tree pythons from individual origins will still maintain a pale yellow body color when they become adults.