Abstract: Pressure straightening can flexibly adjust the straightening method according to different bending situations and repair the deformed workpiece. The straightening effect of a pipe is influenced by its own materials, structural parameters and straightening process parameters. To this end, this paper firstly establishes a finite element numerical simulation model of the pressure straightening process of the pipe, verifies the accuracy of the model, and then investigates the influence of its own material parameters (modulus of elasticity and yield strength), structural parameters (wall thickness and internal diameter) and pressure straightening process parameters (downward pressure amount and pivot distance) of a pipe on the straightening effect. On this basis, a multi-objective optimization model is established with the straightening process parameters (downward pressure amount and pivot distance) as design variables, the pivot distance and down pressure amount as design constraints, and the residual deformation and residual equivalent force after unloading as optimization objectives. The results show that, after optimization, the residual stress of the pipe fittings reduces by 103.207 MPa and the residual deformation reduces by 0.349 mm, which provides reference for improving the pressure straightening effect of the pipe fittings.