Abstract: A power capacitor and a manufacturing method thereof are disclosed. The power capacitor comprises a core installed in major insulation and at least two terminals connected with an external circuit. The core comprises a plurality of welding components mutually overlapped together, each of which comprises a plurality of capacitive elements. Each capacitive element is wound by two aluminum foils and two sets of thin films. Two aluminum foils of each capacitive element are provided with two electrodes extending in opposite directions respectively from the edges of the thin film, and the size a of each electrode is 10 mm to 15 mm. Various capacitive elements inside each welding component are electrically connected through a first batch of multilayer jointly-welded ultrasonic welding structures. Various welding components are electrically connected through a second batch of multilayer jointly-welded ultrasonic welding structures.