Abstract: This paper analyzes the filter and pressure release valve plugging. Based on the analysis results, some methods, such as "virtual pig receiving", replacing the original filter to dismount-free filter and utilizing pigs simultaneously, are put forward. The author consider that the remarkable result to clean the plugging impurity can be obtained by means of this method with following in order and advance step by step. The relative measures and suggestions on the pig wear, selection of pig and pig launching sequence are given out.