Abstract: At present, the proportion of low productivity horizontal wells in low permeability reservoir is high, it is urgent to improve the single well productivity by refracturing. By analyzing the causes of low productivity of horizontal wells, four types of potential wells were classified, and the corresponding reconstruction measures of repeated fracturing and technical pipe string were determined. There were 33 test horizontal wells refractured and the results indicated that the productivity of low permeability horizontal wells had a significant improvement after refracturing. The initial average individual well oil producing rate was 70% above of the first production after refracturing. Therefore, the refracturing technology can prolong the production cycle effectively in low permeability horizontal wells.