The present invention discloses air-tightness test equipment for a turbine reduction gearbox, comprising a base, characterized in that a product mounting plate is arranged and fixed on the base by a support frame, the product mounting plate is provided with a product positioning slot having an opening on its one side; a compression cylinder is arranged over the product mounting plate by a cylinder support plate, the compression cylinder is vertically arranged, and a piston rod of the compression cylinder faces downward and a sealed connector corresponding to the upper part of the product positioning slot is fixed at the lower end of the piston rod; the sealed connector has a cavity in which an inflator is arranged, and the inflator is connected with an inflator pump by a pipeline; the inflator pump is provided with a gas filtration device, the pipeline is provided with a gas valve, and a gas pressure sensor is arranged on the pipeline between the gas valve and the inflator; the compression cylinder, the inflator pump, the gas valve and the gas pressure sensor are connected to a controller, respectively.