Abstract: Operation principle, structure, installation and outfit of process gas for seal and instrument air system of dry-gas seal of compressors are introduced. Dry-gas seal system used presently in R R compressor sets, actual situation of compressor set program and quality of gas piped are analyzed for West-East Gas Pipeline, and relevant technical approaches are provided in the paper based on main factors for failures ahead of schedule of the dry-gas seal of R-R compressor sets.