The utility model provides an extra-high voltage GIS integral insulation test platform based on an oil-immersed reactor, which comprises insulation test equipment and a movable platform with a self-supporting lifting function, and is characterized in that the movable platform comprises a platform chassis, and a main hydraulic cylinder, a bracket and a base which are arranged on the platform chassis; the insulation test equipment is arranged on the movable platform through the bracket and the base; the bracket and the base can be pushed by the main hydraulic cylinder to finish 90-degree overturning and erecting; the insulation test equipment comprises a resonance reactor, a capacitive voltage divider for measurement and a telescopic grading ring, a preset gap is kept between the resonance reactor and the capacitive voltage divider, one end of the resonance reactor and one end of the capacitive voltage divider are fixed to the base, and the telescopic grading ring is installed at the other end of the resonance reactor and the other end of the capacitive voltage divider. According to the utility model, on-site equipment assembly and equipment hoisting are not needed, the occupied space of the equipment is greatly reduced, the equipment can be quickly transferred in a transformer substation, and the on-site alternating current withstand voltage test of the extra-high voltage GIS equipment can be safely and conveniently carried out in the transformer substation.