The fabrication of silver nanoarchitectures (Ag nanofilms) on glass substrates by using a low-cost electrochemical strategy at a proper voltage and polyvinyl alcohol concentration in electrolyte is reported. Ag nanofilms are grown and built with nanoblocks of two-dimensional spherelike nanostructures,which show a highly active and stable surface enhanced Raman scattering (SERS) effect. It shows that the average particle size of silver nanoparticles on the surface of the Ag nanofilms is about 200 nm,and the average size of the nanoblocks is also about 200 nm. The SERS spectra of the human sera for 20 healthy donors were studied on a portable Raman spectrometer,meanwhile,SERS spectra of the serum for the same person was also detected based on different Ag nanofilms prepared with the same conditions. The results show that the SERS effect of human serum is perfect based on the SERS substrate,which will provide a potential tool for analyzing human serum.