The utility model provides a voltage transformer capable of carrying out comprehensive over-current protection. A secondary side of the voltage transformer is provided with an over-current protection device. A secondary lead wire comprises a first secondary lead wire and a second secondary lead wire. The over-current protection device is connected in series between the first secondary lead wire and the second secondary lead wire. The voltage transformer has the advantages that according to the technical scheme, when a short circuit situation is not severe, primary side lead wire heating can be avoided, an insulation layer can be protected, if a mounter and a user carry out misoperation or primary side fuse matching is not proper, the phenomenon that the secondary side lead wires are damaged by burning can be avoided, malignant accidents of voltage transformer bursting caused by the phenomenons can be avoided, using is convenient, and the voltage transformer has the advantages of being simple in structure, convenient to maintain, low in machining cost, high in production efficiency and the like.