The invention provides a weighing filling device for mixed gas insulation high-voltage electrical equipment. The weighing filling device comprises weighing units, a mixing unit and gas cylinders; at least two weighing units and at least two gas cylinders are available, wherein each gas cylinder is arranged on any weighing unit and is internally filled with gas to be mixed; the weighing units are used for obtaining the weight of the gas to be mixed; one end of the mixing unit is simultaneously communicated with all the gas cylinders, and the other end of the mixing unit is communicated with thehigh-voltage electrical equipment; the mixing unit is used for mixing the gas, which is to be mixed and output by all the gas cylinders, and then outputting the mixed gas; the mixed gas is output into the high-voltage electrical equipment. The weighing filling device is provided with the weighing units, the gas cylinders and the mixing unit, so that not only are the ratio and weight of the mixedgas filled into the high-voltage electrical equipment accurately controlled, but the filling device provided by the invention is also simple in structure, convenient to use and easy to manufacture; therefore, the manufacturing cost of the filling device is greatly lowered.