The invention discloses an easy-to-install high voltage transformer which comprises a substrate, a flat nut, an axial retaining ring, press claws and a voltage transformer. The substrate is provided with a sliding tube, radial guide limiting holes, retaining tables and an annular clamping groove; all the radial guide limiting holes comprise communicated guide sliding holes and anti-disengagement sliding holes; the voltage transformer is fixedly arranged on the peripheral wall of the sliding tube of the substrate in a sleeving mode; each press claw is provided with a pressing plate part, a guide sliding block part and a driving thread part; the guide sliding block part of each press claw is provided with a guide part located in the corresponding guide sliding hole, an anti-disengagement part located in the corresponding anti-disengagement part and a limiting part located on the outer side of the sliding tube of the substrate; the axial retaining ring is fixedly connected in the annular clamping groove formed in the peripheral wall of the sliding tube of the substrate in a clamping mode; the flat nut is rotatably arranged on the peripheral wall of the sliding tube of the substrate; a plane thread part which is used for being matched with the driving thread parts of the press claws in a meshed mode is arranged at the side end, connected to the retaining tables in an abutting mode, of the flat nut; the flat nut drives the plane thread part to conduct reciprocating rotation so as to drive the press claws to be close to or away from the center of the sliding tube. The easy-to-install high voltage transformer is easy to install and locate.