Be/Cu/HR-1 stainless steel is bonded at 800℃ by hot pressing under different pressure. Optical microscopy, microhardness tester, scanning electron microscopy （SEM）, auger electron spectroscopy(AES) and X-ray diffraction （XRD）were used to study microstructure and elements distribution of the steel at the bonded area. The relationship of composition and microstructure with pressure is discussed. The results show that pressure will lead to dynamic recrystallization and diffusion creep, and also has effect on the width of diffusion bonding zones, sizes of grain and amounts of intermetallic compound at the diffusion bonding zones. Texture is formed in matrix or at diffusion bonding zones under uniaxial pressure. The intermetallic compound formed along grain boundary is a main reason for causing breakdown of the bonding area. By the reducing holding pressure or time, the intermetallic compound can be reduced and the bonding strength can be improved.