AbstractDiethyl‐benzyl‐[3‐methyldimethoxyl)]silpropyl ammonium chloride (DEBSAC) was synthesized from N,N‐diethyl‐aminopropyl‐methyldimethoxysilane (DEAPMDES) and benzyl chloride. Diethyl‐2,3‐epoxypropyl‐[3‐methyldimethoxyl)] silpropyl ammonium chloride (DEEPSAC) was synthesized from DEAPMDES and epoxy chloropropane. Trimethyl‐[3‐methyldimethoxyl)] silpropyl ammonium chloride (TMSAC) was synthesized from trimethylamine and γ‐chloropropylmethyldimethoxysilane (CPMDMS). The products were characterized by 1H NMR, 13C NMR, and IR. The surface tension measurements showed that the organosilicon quaternary salts exhibit a lower surface tension and a lower critical micelle concentration (CMC) than the hydrocarbon counterparts. The plate count method experiments illustrated that DEEPSAC has a better degree of antibacterial activity against Escherichia coli than DEBSAC. The solubilizing effects of the organosilicon quaternary salts on organosilicone were studied by pseudo‐ternary phase diagrams of synthesized products/cosurfactant(n‐butanol)/water/octamethylcyclotetrasiloxane. The solubilizing activities decreased in the order of TMSAC > DEBSAC > DEEPSAC.