Casing deformation in shale gas wells during multi-fracturing has seriously affected the efficiency and safety of shale gas production in China. Casing deformation leads to the failure of subsequent fracturing construction, which seriously affects the fracturing construction effect. The characteristics of casing deformation in Weiyuan and Rongxian shale gas field were statistically analyzed, and the main influence factors were obtained. According to different fracturing sequences, the finite element software was used to compare the stress changes of the near wellbore during the fracturing process of shale gas wells. The results show that the casing deformation in shale gas wells mainly occurs near the heel of the horizontal section, and shear failure is the main type of casing deformation in Weiyuan shale gas field; in heterogeneous deep shale, the multistage hydraulic crack initiation and expansion leads to non-uniform accumulation of ground stress around the wellbore, which induces natural crack slippage, which in turn causes shearing and collapse of the casing, and as the distance between the wellbore and the crack increases, the compressive stress of the casing is gradually reduced. Avoiding fractures in the fracture development zone and reducing the scale of the fracturing can reduce the risk of casing failure. This study further reveals the mechanism of casing deformation during multi-fracturing in shale gas wells, and proposes fracturing measures for casing integrity. The results demonstrated in this paper can provide the theoretical basis for preventing casing deformation during fracturing in shale gas wells.