Nano dendrites serving as surface enhanced Raman scatting（ SERS） substrate isfabricated in pre-set mirco-domains using AC electrodeposition method. The morphology

location and growth direction can be controlled effectively through tuning AC and DC biased voltage. Growth mechanism of Raman substrate is discussed from two point of views of electrochemical process and electric fluid coupling field. Laser confocal microscope Raman experiment further show that

using 4-mercaptopyridine as the pointer molecules

the substrate has good Raman activity.