以十二烷基二甲基叔胺和环氧氯丙烷为主要原料，通过一步法制备对称型阳离子双十二烷基g-双季铵盐杀生剂(DBAS)，考察了药剂投加量、pH值、水温和杀菌时间对异养菌杀菌效率的影响. 结果表明，在投药量10 mg/L、杀菌时间2~10 h、pH值6~9、水温25~45℃的条件下，DBAS对异养菌的杀菌率均能保持在90%以上. DBAS对异养菌的杀菌机理主要是：(1)通过吸附、网捕、架桥等形式将异养菌絮凝包裹，使局部药剂浓度增大而使细菌死亡；(2)DBAS分子结构中2个带正电荷的N+官能团和?OH使其更易吸附到异养菌细胞表面，2个疏水基?C12H25和亲水基分别同时深入到类脂层和蛋白层，使其变性死亡.

Didodecyl g-biquaternary ammonium salt (DBAS) was synthesized from di-methyl-dodecylamine and epoxy chloropropane by one-step processs. The effects of DBAS dosage, pH value, water temperature and antibacterial time on the sterilization efficiency of heterotrophic bacteria were investigated. The results showed that its sterilization rate was above 90% in 10 h when the dosage was 10 mg/L, pH value from 6 to 9 and water temperature from 25℃ to 45℃. The main anti-bacterial mechanism was that by adsorption, netting and bridging, heterotrophic bacteria were flocculated with DBAS, which made local drug concentration increase to cause the death of bacteria. Both positively electricity quaternary ammonium N+ groups and ?OH made DBAS in water adsorb to the surface of heterotrophic bacteria more easily. Two hydrophobic groups of ?C12H25 and the hydrophilic groups penetrated into the lipid and protein layer inside the membranes of heterotrophic bacteria cells, modified them, and killed heterotrophic bacteria finally.