The utility model provides a transformer anti -theft device, the utility model relates to a transformer field, its structure is: fixing on the wire pole of cross arm (2), be provided with transformer (10) on cross arm (2), fixed be provided with channel -section steel (3) in bottom of transformer (10), detain in (1) is detained to the spill cross arm (2) and channel -section steel (3), be provided with the bolt hole on the spill knot (1) and channel -section steel (3), pickproof lock (9) are buckled (1) and channel -section steel (3) bolt hole on through the spill and are locked transformer (10), terminal inside be provided with triangle nut (8) of pickproof lock (9), be provided with on outside pickproof lock (9) of triangle nut (8) lag (4), the cover is gone up in triangle nut (8) has spanner (7), the end of spanner (7) is fixed with torque tube (6) and handle (5). The utility model has the advantages of it is effectual to prevent burglary, be convenient for install and dismantle, convenient operation uses in a flexible way.