Corner cracking phenomenon in square and rectangular pipes during roll bending, which has become a key issue that seriously restricts the quality of square rectangular tubes. In order to address this issue and find a way to control the cracking defect, a comprehensive study was conducted. Firstly, the mechanical properties of the MS1180 material were obtained by uniaxial tensile, notched tensile and plane strain experiments. Three fracture criteria, Ayada, Rice-Tracey and standardized Cockroft-Latham criteria, were calibrated using these test date, and the criterion with the smallest prediction error was selected. This criterion was then used to construct a square rectangular tube roll bending cracking model. Next, using COPRA RF design software and finite element MARC simulation professional software of roll bending, a three-dimensional finite element model for continuous roll bending of square rectangular tube was established in combination with the actual production conditions. The accuracy of the model was verified by roll bending experiments. Finally, scanning electron microscopy and metallographic microscope were used to observe the cracks and fractures of the rectangular tube. The stress-strain distribution of the square rectangular tube during continuous roll bending was investigated using the finite element model, and the effects pass number, corner forming radius and frame spacing on the stress-strain distribution of the corner of the rectangular tube were analyzed. It is found that the initiation of cracking point of the material occurs near the outer layer of the corner. In addition, the cracking fracture is analyzed, which reveals that the cracking mechanism is quasi-cleavage fracture, where excessive principal stress on the corner shear surface leads to cracking. Increasing the number of roll bending passes, the forming radius of the square rectangular pipe corner and the spacing between the frames can effectively reduce the occurrence of cracking issues. These findings provide a theoretical basis for solving the problem of cracking in the corners of square rectangular pipes in the future.