Abstract: With the injection of polymer, the injection pressure was decreased gradually and was unable to satisfy the injection allocation rate during the polymer flooding, which wound caused the under-pressured injection, such as intermittent injection, and influenced the effect of polymer flooding seriously. General stimulation treatments such as hydraulically fracturing and chemical blocking removing are characterized by short validity period and poor action effect. This paper analyzed the reasons of plugging in physics, chemistry and biology terms and summarized the blocking removers common used at home and abroad, and then analyzes the suitability of different blocking removing measures according to the main reason of causing blockage. The results show that in order to obtain the ideal effect, we need to form the blockage reasons diagnostic mechanism, and adopt various practices to cooperate each other.