Abstract: The liquid film solution diffusion welding of ZCuBe2.5alloy were conducted using Cu-based alloy powder as welding materials.It is found that the microstructure consists of homogenous,fine ct-Cu e-quiaxed grains and intercrystal metallic compounds,and the base metalnear the interface still remains the original morphology of coarse ct-Cudendrites and intercrystal,peritectic phases.The filler metal joins basemetal perfectly,and the transition solution layers with 130-160 trm thickness form due to mutual diffusion of interface atoms.As the increase of mesh size,the sizes of equiaxed grains decrease gradually;the weld mi-crestructure becomes more fine;the thicknesses of diffusion transition layer decrease;the interface microstructure becomes fine and close;the joint tensile strength increase;the heat-affected zone become narrow;and the hardness distribution tends to be more reasonable.Due to the existence ofthe temperature gradient,the liquid film solution diffusion bending canrealize the high strength bonding in a short time.