Abstract: In order to form a more complex fracture network system in staged fracturing of horizontal wells so as to improve production rate,a new optimization method for perforation spacing has been established including a mathematical model of fractures induced stress filed on the basis of homogeneous and isotropic 2D plane strain model,and the diversion of maximum and minimum horizontal principal stress direction as the fracture reorientation criterion according to the general process of staged fracturing of horizontal wells.The results showed that the induced stress decreases gradually with the increase of fracture spacing.When the fracture spacing is constant,the induced stress in the direction of minimum stress is larger than that in the direction of maximum stress,and the difference between them first increases then decreases.The perforation spacing of horizontal wells in western Sichuan Basin was optimized by this method.Compared with the surrounding wells with large spacing of perforation set,the post-fracturing production rate of the horizontal wells with optimized perforation spacing improved greatly,which demonstrates this optimization method of perforation spacing has guiding significance to the staged fracturing design of horizontal wells in low-permeability reservoirs to some extent.