Abstract: The causations which may make the gas formation plugging are analyzed according to the formation damaging specialty of Kela-2 gas field. Trials of non-acid plug removal chemical agent have been done according to the drilling fluid using in the field and plug removal agent FS has been developed. It can cleanout polyment dirt such as bitumen and lubricant, ravel emulsification plug, reduce surface tension of filtrate and relieve water-lock of pore throat. The agent also has stabilization effect to clay mineral. The test result of core indicate that the FS can ravel contamination of drilling fluid effectively.