The invention provides an immovable string plug removal method, comprising the following steps: a) testing pressure, including testing pressure of an oil-water well string, and recording wellhead pressure; b) injecting acid liquor used for removing plug; injecting the acid liquor used for removing plug into the oil-water well string, the acid liquor used for removing plug being injected into a plug removal target stratum in one time; c) shutting in a well, after shutting in the well for 12 hours, recovering normal production. The immovable string plug removal method uses an original production string of an oil-water well to perform acidizing treatment, improves effectively utilization rate of the acid liquor used for removing plug, and improves acidification effect, effectively removes plugging of the target stratum. The method saves operation cost of general plug removal and layering plug removal, and shortens construction cycle, and improves production efficiency.