The BiFeO3 films were deposited on the SrTiO3 (001) substrates via tuning the thickness of the SrRuO3 (SRO) bottom electrode by pulsed laser deposition. The macroscopic ferroelectric and dielectric properties were dramatically impacted by the various nanoscale domain structures for both films due to the tunable SRO thickness. The nanoscale domain switching behaviors for both films were investigated via piezoresponse force microscopy, and results suggest that the domain structure could be changed by tuning the strain state. The surface potential investigation indicates that strain helps increase data storage density and stability. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.3698155]