Several studies have been done on the acid system and acidizing operation parameters in order to improve acidizing effect on high water⁃cut horizontal well of CFD11⁃2 oilfield.The results show that the corrosion capacity to rock of mud acid is higher than fluoroboric acid and muti⁃hydrogen acid,while the retard capacity to rock of muti⁃hydrogen acid is superior to mud acid and fluoroboric acid.The results by simulate on acidizing operation parameters show that high injection rate is favorable to improving acidizing effect,and the pollution can be removed effectively when acidizing radius is 1~2 m.Soil acid with strong dissolution ability and polyhydrogen acid with high retardation ability were firstly used in acidizing operation of three wells in Caofeidian 11⁃2 oilfield.After field operation,the average daily fluid increment of three wells was 362 m3/d,and the average daily oil increment of single well was 16.4 m3/d.The effect of plugging removal and stimulation was remarkable.