Copper powder is prepared by electrolysis, and additives Sodium dodecyl benzene sulfonate (SDBS) and polyvinyl pyrrolidone (PVP) are added to the electrolyte. Through the synergy effect of the two additives, the shielding effect between metal atoms is enhanced, and as a consequence the microscopic morphology is changed and it the powder performance is improved. Scanning electron microscopy (SEM), x-ray diffraction (XRD) and Electrochemical Impedance Spectroscopy (EIS) are used to characterize the copper powder. The results show that when the content of SDBS and PVP is 5 g l−1 and 1.5g l−1 respectively, the new type of thin and long dendrite copper powder can be obtained by electrolysis.