Various high-end equipment relies on titanium alloy plate-fin structure (PFS) as core components, owing to their remarkable advantages in terms of low density, superior mechanical strength and enhanced corrosion resistance. Brazing assumes a pivotal function in PFS connections, whereby the localized concentrated heat during the welding procedure can precipitate intricate structural deformation and generate residual stresses. A thermo-mechanical coupling model was developed, taking into account the service performance criteria of PFS. The effects of process parameters and clamping methods on the post-welding residual stress and deformation of PFS were investigated. The analytical expressions for the relationship between the process parameters and the stress/deformation were obtained by using the simulation outcomes. The constraint on the partition in the vacuum brazing process determines the extent of deformation and residual stress of PFS, with higher constraint leading to lower values. PFS generates z-directional displacement and y-directional warping deformation, and the weld seam between the fin and the partition is prone to stress concentration. As the brazing temperature and holding time increase, the PFS induces more deformation, while the residual stress value decreases. However, the deformation amount reaches a plateau when the holding time exceeds 30 min.