The invention discloses an ultra-high voltage pulse transformer, which comprises a transformer component and an oil cylinder, wherein the transformer component is connected with the oil cylinder in a rapid connecting manner of a socket and a plug; the transformer component comprises a main transformer, a bias inductor, a capacitive voltage divider, a current transformer and an equipotential capacitor, which all are arranged on a semicircular bottom plate to be conveniently and quickly installed and maintained; the main transformer is formed by combining multiple groups of iron cores which are rectangular cutting iron cores in parallel; and corners of all iron cores are rounded. According to the ultra-high voltage pulse transformer, multiple problems that a traditional ultra-high voltage pulse transformer is huge in volume, heavy, not beautiful in appearance, complicated in structure, difficult to produce, assemble and maintain, too long in pulse rising time and the like, and the problem that surroundings and operators are harmed due to the fact that the radiation dose of dangerous rays exceeds the standard in online charging work are solved; the production cost is reduced; and the production efficiency is improved.