In　order　to　overcome　the　deficiency　of　the　traditional　methods　in　natural　gas　process,　a　new-type　of　dehydration　unit　for　natural　gas　was　briefly　described　and　its　basic　structure　and　working　principles　were　presented.　We　got　the　parameters　distribution　in　the　supersonic　separator　by　getting　the　reasonable　assumption,　geometric　model　and　time　averaged　equations　in　tensor　form.　From　the　results,　a　shock　wave　is　found　between　-400　mm　and　-200　mm　which　is　consistent　with　the　experimental　results.