The invention relates to a small ellipsoid type plasma reaction chamber and a design method thereof. The small ellipsoid type plasma reaction chamber comprises a chamber body, a settling chamber and acoaxial antenna, wherein the settling chamber and the coaxial antenna are arranged in the chamber body; the metal chamber body is in a shape of an ellipsoid of which the lower part is trimmed, the diameter Z of the long axis of the ellipsoid-shaped metal chamber body is equal to 430 to 440 mm, and the radius R of the short axis is equal to 160 to 170 mm; the settling chamber is composed of a settling base station and a quartz clock cover, the settling base station is parallel to the short axis of the ellipsoid and is arranged in the lower trimming position of the chamber body in a sealing mode, and the quartz clock cover coaxially covers the settling base station; and the coaxial antenna is made of cylindrical copper materials and is arranged at a gap in the upper end of the chamber body,the microwave coupling mode of the plasma reaction chamber is antenna coupling, and the microwave resonance mode is TM033. The microwave plasma CVD device of the plasma reaction chamber has the samemicrowave focusing capability as a traditional TM036 type device, but the size is one half of the traditional TM036 ellipsoid type device, and the small ellipsoid type plasma reaction chamber has theadvantages of reasonable and compact structure, low cost and low processing difficulty and has good application prospects.