Abstract: A direct chlorination system and device characterized by feeding of liquefied chlorine into water without vaporization in a process that liquefied chlorine from a source liquefied chlorine cylinder is led to a liquefied chlorine settlement cylinder for removal of solid impurities, a metering pump for a pressurization and flow rate control at the metering pump and a liquefied chlorine feeder for mixing with and dissolving in pressurized water to become a high concentration chlorine solution which is then led to a water injector for feeding into a rapid water filter, a mixing basin and a clearing water reservoir for reaction and disinfection before city water is sent to a city water distribution network, and possessing the following merits: upgrading potable water quality, minimizing initial investment, lowering operating cost, and providing a simply but reliable, easy-to-control device that can facilitate water works automation.