The invention relates to a novel outdoor anti-theft transformer. The novel outdoor anti-theft transformer comprises a transformer box body, a transformer box cover, an iron core and a coil winding, wherein the coil winding wraps the iron core in a winding manner, the iron core and the coil winding are arranged in the transformer box body, the transformer box body is filled with transformer oil, an oil pillow is arranged on the transformer box cover, the transformer box cover is tightly fixed on the transformer box body by an anti-theft bolt, an alarm protection structure is arranged between the transformer box cover and the transformer box body, a sealing gasket is further arranged between the transformer box cover and the transformer box body, a high-voltage outgoing line sleeve and a low-voltage outgoing line sleeve are further arranged on the transformer box cover, main cooling pipes are arranged at a front side and a rear side of the transformer box body, auxiliary cooling structures are arranged at a left side and a right side of the transformer box body, an anti-theft oil discharge valve is arranged at the bottom of the transformer box body, and the anti-theft transformer also comprises a high-voltage wiring structure and a low-voltage wiring structure and further comprises a broken line detection device.