The invention discloses a transformer capable of controlling magnetic flux leakage. The transformer comprises lung lobe type shields which are arranged in yoke cushion blocks at the upper end and the lower end of a transformer body, a copper shield which is arranged on the inner wall of a transformer oil tank, bar-type magnetic shields which are paved at the upper end and the lower end of the copper shield and are composed of at least one magnetic shielding bar respectively, and L-shaped copper plates which are arranged at the positions of tank edges of an upper joint and a lower joint to be connected with the copper shield. According to the transformer, the problems such as local overheating of metal structural members inside the transformer and local overheating of the transformer oil tank and connecting bolts of the upper joint and the lower joint can be solved effectively.