The invention discloses a dry gas sealing device for a technical screw compressor and an application system thereof. The dry gas sealing device is characterized by comprising two sets of single sealing mechanisms with the same structure, wherein each set of single sealing mechanism comprises a static ring component, a moving ring component, a push ring and a spring component, wherein the static ring component is fixedly connected with a gland, and the moving ring component, the push ring and the spring component are fixedly connected with a shaft sleeve. The application system comprises a technical screw compressor, two dry gas sealing devices, two labyrinth sealing devices, two groups of gas flowmeters of sealed gas, a front-end gas input device and a sealed gas input device, wherein the two dry gas sealing devices and the two labyrinth sealing devices are symmetrically arranged at two ends of the shaft of the technical screw compressor. The invention also discloses an application method of the application system.The dry gas sealing device for the technical screw compressor of the invention has self adaptation and non-contact characteristics, can ensure reliable operation of dry gas sealing by matching the combined application system which has balancing cavity pressure relief, labyrinth seal obstruction, front-end nitrogen protection and dry gas sealing, and is especially suitable for high-pressure technical screw compressors with high rotary speed.