Sulige gas field is the largest low permeability natural gas field discovered and developed in our country, and it is also a typical representative of tight sandstone gas field, which has the characteristics of low production and fast pressure drop per well. After the long-term production of gas Wells, the number of Wells that cannot produce normally increases year by year due to the blockage of the reservoir near the well. At present, the study on the clogging mechanism in the near-wellbore area of gas wells is not sufficient, and the treatment agent for removing clogging and water locking is not targeted enough. Therefore, the study on the fouling and clogging mechanism of Sulige gas well is carried out to confirm that corrosion products, water scaling products and solid sand particles are the main causes of wellbore and reservoir clogging. Developing and evaluating the working fluid for removing blockage and water lock in the reservoir, the dissolution rate of blockage reaches 90.6% at 90 ℃ and 24 h. The field test of 5 Wells including SD**C1 was completed, and the effective rate of the measures was 100%. After the measures, the average daily output increased by 0.2–0.6 × 104m3 per well in that year, and the average cumulative gas output increased by 75.20 × 104m3 per well. The production recovery effect was remarkable, providing a powerful way for the recovery of old Wells in Changqing low permeability gas field.