In this work, the synthesis of dichlorocyclopropane, from a phase-transfer catalyzed reaction of chloroform and olefins (1-octene or 1,7-octadiene), was carried out in an alkaline solution of NaOH/chloroform two-phase medium. Trialkylammonium propansultan, a zwitterionic compound, acts as a new phase-transfer catalyst of high reactivity to produce high yields of dichlorocyclopropane. Dichlorocarbene (: CCl2), which is an active species to react with olefins to produce dichlorocyclopropane in the organic phase, is generated from the reaction of chloroform, sodium hydroxide, and trialkylammonium propansultan as phase-transfer catalyst at the interface between two phases. The dichlorocyclopropanation is dramatically enhanced by adding a small quantity of trialkylammonium propansultan. An interfacial reaction mechanism was proposed to explain the reaction characteristics. A pseudo first-order rate law is used to describe the reaction rate at high alkaline concentration solution (> 50 wt% NaOH). There is detailed investigation of the reaction kinetics, including the effect of the reaction conditions - the agitation speed, temperature, phase-transfer catalysts and their amounts, the amount of chloroform, the amount of 1-octene, inorganic salt (NaCl and Na2SO3), and alkali concentration - on the conversion of 1-octene.