Abstract: Aluminum composite substrate is an ideal cooling substrate for high-power module chip，the preparation of Aluminum Composite Substrate often appears oxidation corrosion in the non-vacuum environment，which results in low density substrate that can not match chip.This paper presents a vacuum chamber for the preparation of Aluminum Composite Substrate.Based on the shape，size and material selection made of vacuum chamber and wall thickness calculation，the structure of vacuum chamber was completed and its static and dynamic seal structure was designed.The maximum stress and deformation of vacuum chamber was simulated and analyzed by ANSYS software for meeting the strength and rigidity of the vacuum chamber，which created a sealed and stable environment for preparation of Aluminum Composite Substrate by vacuum thermo-electric extrusion.