Abstract: This paper expounds the study of multiple injection closed acid-fracturing technology,which is developed by system engineering method in accordance with the low permeability gas reservoir in the centre port of Shanganning basin.It introduces some important conclusions from simulation research on the computer softwares for multiple injection,two-dimensional and pseudo-three-dimensional acid-fractuing design,and presents the design principle and results evaluation method of field treatment,as well as field appliaction results.The paper stresses emphatically that the multiple injection closed acid-fracturing technlogy would be a best method to increase the production of carbonate gas reservoir with low permeability or poor Permeability.