Abstract: Due to long-term waterflooding development of Tuha Oilfield,exogenous injury caused by injected water and formation endogenesis injury increasingly accumulate in deep formation.The effect of conventional acidizing treatment is not good.In this paper,long core injury simulation experiment is conducted to research the deep injury characteristics and the plugging removal and acidization mechanism.Deep plugging removal is realized based on the synthetic application of retarded plugging removers and technological process.Diagnosis analysis is made on overall injury of single wells and parameters optimization design is conducted by applying the expert system of AcidGuide.Good effect is achieved in field application,which may be a good reference to intensified injection measures of injection wells in similar low permeability reservoirs.