For the negative influence of clay on the rheological properties of cement slurry containing polycarboxylate superplasticizer,three cationic gemini quaternary ammonium were synthesized by triethylamine with 1,4 dibromopropane,1,5 dibromopentane and p dibromobenzyl respectively through quaternization. The corresponding products were labeled as KN1, KN2, and KN3, respectively. Then they were compounded with polycarboxylate water reducing agent RS 1 to reduce the clay sensitivity of the water reducer. The molecular structures of KN1, KN2 and KN3 were characterized by FTIR and 1H NMR. The gemini quaternary ammonium salt properties of the compounded system were evaluated by measuring fluidity of cement paste. Meanwhile, the dispersion, hydrophobicity and adsorption properties of the compounded system were investigated by XRD, water contact angle and total organic carbon(TOC). The results indicate that when the content of montmorillonite is 3%(by mass), KN1, KN2 and KN3 can significantly improve the fluidity of cement paste. Among those, KN3shows the best anti clay performance.