The invention discloses an oil gap insulation discharge testing platform, and the platform comprises an oil tank for the sealing storage of transformer oil, and a bushing for applying a voltage. The tail end of the bushing is located in the oil tank, and is connected with a voltage-sharing ball. The interior of the oil tank is also provided with a plate electrode, and there is an interval between one end of the plate electrode and the voltage-sharing ball. The other end of the plate electrode is grounded. The oil tank is provided with an impurity inlet for adding impurities, and a gas inlet for injecting gas. The impurity inlet is provided with an impurity adding valve for controlling the entering of impurities. The gas inlet is provided with a gas injection valve for controlling the entering of gas. The platform can control the contents of the impurities and gas in the oil can be adjusted according to the actual demands, controls the test variables, and simulates the conditions of actual operation. The platform can be used for carrying out a plurality of tests, saves the cost, and facilitates the deep analysis and research of long oil gap discharge forming principles and influence factors.