The utility model belongs to field of electric power application, and particularly relates to a large-scale transformer partial discharge test shielding case. The large-scale transformer partial discharge test shielding case includes a shielding case body, a clamp, and a transformer sleeve. The upper part of the transformer sleeve is provided with a U-shaped shielding cover, a welding point on the inner top end of the shielding case body is connected with the clamp through a bare copper wire, and hand holes are arranged in the side wall. When the shielding case is used, testers install the shielding case on the transformer sleeve of A, B, and C phases, and because there is more interference sources on site, the shielding case makes the electric field distribution at the sleeve wiring part more uniform, and prevents the discharge capacity generated by breakdown air from mixing into the measured value, thereby achieving the effects of uniform distribution of electric fields.