Abstract: Yaha gas field is a large gas condensate field with high pressure cycling gas injection development to partly maintain formation pressure. Since the gas reservoir was put into production, positive development effect has been achieved, but at present, the gas reservoir is confronted with such problems as serious gas breakthrough in some of the production wells, rapid growth of GOR and sharp decline of condensate oil production rate. By combined testing of MDT (modular formation dynamics tester), the migration laws of recycled dry gas ware discovered, and the longitudinal distribution feature of subsurface fluid was precisely identified. So the condensate gas concentration zone was confirmed, providing the bases for adjustment of developing the gas condensate reservoir