Disclosed is a method for forming internal and external profiles of stationary and movable scroll plates which have a variable wall thickness, comprising a stationary scroll plate and a movable scroll plate. The movable scroll plate is formed by rotating the stationary scroll plate along the center thereof by 180°. The stationary scroll plate and the movable scroll plate are each composed of internal and external profiles. The distance between the internal and external profiles is the wall thickness of the plates. The beneficial effects of the present invention are as follows: by means of calculation equation expressions of the internal and external profiles of the movable scroll plate and the stationary scroll plate, it is derived that the pressure of a crescent-shaped working chamber formed by means of the mutual meshing of the internal and external profiles of the movable scroll plate and the stationary scroll plate gradually decreases from the head to the tail of the center of the plates, the required wall thickness gradually decreases, and the scroll plates which have a variable wall thickness use less material to ensure tolerance of a sufficient amount of pressure strength, thus improving the smoothness of compressed gas of the scroll plates while further reducing the concentration of stress.