Polyether ploysiloxane(EPEPS) 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 (m-psi-m) were synthesized by quaternarization of EPEPS with N,N-dimethyl long chain alkyl amine in the presence of anhydrous ethanol and HCl aqueous solution. The structure of m-psi-m was analyzed using IR and 1HNMR. The influences of hydrophobic chain length of m-psi-m on their surface activity, critical micelle concentration, wetting ability and emulsifying stability were investigated in detail. Experimental results show that with increasing of hydrophobic chain length, surface activity and wetting performance of m-psi-m decreased, critical micelle concentration and emulsifying stability increased.