Sulfate reducing bacteria (SRB) were most common bacteria involved in microbiologically influenced corrosion (MIC). In this paper, the influences of surface free energy and electrochemical polarization on sulfate reducing bacteria (SRB) attachment were investigated. Microbial adhesive to hydrocarbons experiment and zeta potential test showed that SRB were relative hydrophobic and were negative charged. SRB showed affinity to substratum with higher water contact angle and its biofilm formation led to alterations in the hydrophocibity of the substratum surface. The mild steel was used to systematically examine the effect of electrochemical polarization on SRB attachment. At -800mV (vs.SCE), the sessile number was similar to those without polarization. At -950mV and -1000mV, the polarization promoted SRB attachment. At -1100mV and -1200mV, the adhered cell number decreased sharply compared to those at -1000mV. SRB attachment was inhibited, at an applied potential of -1300mV. These results indicated that the infuence of negative polarization on SRB attachment was dependent on applied potential.