Abstract: Powdered copper having an average powder size of 1?μm was sintered by spark plasma sintering(SPS) at different sintering pressure.The relationship of relative density and microstructure of compact to initial pressure during the heating up period and dwelling pressure is studied.Results showed that the relative density of sintered copper was above 98% and its grain fineness was about 10?μm,when sintered by the process of loading 1?MPa as initial pressure and 50?MPa as the dwelling pressure,and a sintering temperature at 800?℃.In the mean time,the density distribution of sintered copper made by SPS along depth was different to the compact made by traditional double-action compacting.Its surface density is lower than the central density.