The invention discloses a controllable switching multi-gear output intelligent transformer apparatus. The controllable switching multi-gear output intelligent transformer apparatus comprises a transformer and an array type electric control contactor, wherein the primary winding of the transformer comprises one or more than two taps, or the secondary winding of the transformer comprises one or more than two taps, or the primary winding and the secondary winding of the transformer both comprise taps; the primary winding and the secondary winding of the transformer can be interconvertible; primary winding and the secondary winding of the transformer both comprise three phases; the transformer apparatus comprises an input end and an output end; the input end is connected with the primary winding through one or more three-phase contactors while the output end is connected with the secondary winding through one or more three-phase contactors; the array type electric control contactor receives an external voltage level switching instruction and executes a contactor action which is corresponding to the voltage level switching instruction so as to switch the combination of the input end and the output end of the transformer apparatus. The apparatus can output multi-gear voltages; the power supply voltage can be subjected to voltage boosting and voltage drop of different levels; and requirements of multiple kinds of test objects can be satisfied.