The invention specifically relates to a separator and nozzle holding-clamping testing device for a heavy water reactor loader-unloader. The separator and nozzle holding-clamping testing device for a heavy water reactor loader-unloader includes a gas source (1), a holding-clamping assembly pressure-reducing valve (2), a first motion assembly pressure-reducing valve (3), a second motion assembly pressure-reducing valve (4), a holding-clamping assembly flowmeter (5), a first motion assembly flowmeter (6), a second motion assembly flowmeter (7), a third motion assembly flowmeter (8), a holding-clamping assembly solenoid valve (9), a first motion assembly solenoid valve (10), a second motion assembly solenoid valve (11), a third motion assembly solenoid valve (12), and a holding-clamping assembly flow control valve unit (13). The separator and nozzle holding-clamping testing device for a heavy water reactor loader-unloader is designed and manufactured according to the control principle and control flow of design of the separator assembly and the nozzle holding-clamping assembly. For the separator and nozzle holding-clamping testing device, the driving power of the equipment assembly utilizes the compressed air to replace water and oil; the solenoid valves are used to realize direction control of each part; and the compressed air is connected with the solenoid valves through the pressure-reducing valves so as to guarantee that suitable pressure can be provided to drive.