Epoxy-modified polyether ploysiloxane (EP-PSix-EP, x=30cst, 100cst, 800cst) was synthesized by ployethylene glycol diglycidyl ether and polydimethylsiloxane using TBAB and NaOH as catalyst, acetone and n-hexane as solvent. Then, quaternary ammonium organic silicon gemini surfactants (C12-PSix-C12, x=30cst, 100cst, 800cst) were synthesized by quaternarization of EP-PSix-EP with N,N-demethyldodecylaminein, in the presence of anhydrous ethanol and HCl aqueous solution. The effect of spacer length on characteristics of quaternary ammonium organic gemini surfactant was investigatedby measurement of surface activity, wettability, emulsion stabilityand antibacterial property.Experimental results showed that with decreasing of siloxane spacer length, emulsion stability and wettabilityof C12-PSix-C12 increased. Three kinds of quaternary products have antibacterial properties. Decreasing the siloxane spacer length of C12-PSix-C12, the antibacterial properties increased.