Abstract: This contribution focuses on the analysis of residual stress and thermal deformation of microminiaturized nickel base brazing stainless steel plate-fin structure after vacuum brazing. A finite element method is utilized to conduct the thermal-mechanical analysis for brazing such three layers structure, and the actual heating history of vacuum brazing and temperature-dependent material properties of plate-fin and filler metal are considered.The thermal cycles during brazing, thermal distortion and residual stress after brazing are reported. The results show that plates and fins have different deformation features, and complex stress state appears in the region of joint fillets which may induce the crack generation and propagation of brazed joint and result in the structure failure in service. It is noteworthy to control appropriate brazing time to get preferable joints