Winding vibration characteristics of a three-phase transformer with respect to the DC disturbance problem are studied under AC/DC hybrid operation. The DC invasion state equation of a Y/Δ transformer is established, and the winding current is identified through electromagnetic coupling iteration while the winding vibration is analyzed by a vibration harmonic response model. The DC biased electromagnetic characteristics of the transformer under different operation modes are simulated and calculated to examine the variation of winding current and its vibration characteristics under different DC disturbances. At the same time, the winding vibration under different conditions is compared and the rules are summarized. A dynamic model test platform for the three-phase transformer is built, and a DC disturbance experiment of 380 V transformer under no-load and load operation is carried out to obtain winding current and vibration information. The simulation result is verified by experimental data. This work is supported by National Natural Science Foundation of China (No. 51507027) and Science and Technology Development Plan Project of Jilin Province (No. 20190303007SF).