The present application provides a continuous preparation system and method for vinylidene chloride. In the present application, by coupling two stages of high gravity reactors, the product vinylidene chloride and water vapor are distilled from a reaction system in form of an azeotrope by adopting a water vapor steam stripping method, and the product obtained using the method has high purity. In addition, by combining steam stripping and high gravity, trichloroethane and alkali solution are rapidly mixed for mass transfer, and the product vinylidene chloride is rapidly distilled from the reaction system in form of the azeotrope (based on rapid diffusion of water vapor), such that the reaction proceeds continuously towards the direction of producing vinylidene chloride, thus significantly improving the conversion rate. As proved by a test apparatus, the present application can stabilize the purity of the vinylidene chloride product at 98% or more (mass fraction), decrease the TOC value of chloride salt wastewater to 100 mg/L or less, and decrease the consumption of materials and the cost of subsequent salt-containing wastewater treatment.