The present invention relates to a loop-route production method and system for polyvinyl chloride, and belongs to the intersecting fields of coal chemicals, polymer materials and chemical machinery. Limestone and carbon materials such as coal are reacted in an oxygen-enriched high temperature furnace to obtain calcium carbide and carbon monoxide, and then acetylene and carbon monoxide are respectively produced from calcium carbide and dichloroethane (obtaining ethylene, etc., through methanol or ethanol); both of the end products are combined to form a closed-loop; acetylene and dichloroethane are reacted to produce a vinyl chloride monomer, which is polymerized to obtain polyvinyl chloride. The system of the present invention mainly includes a device for pulverizing and mixing solid raw materials, a device for conveying solid materials, an oxygen-enriched calcium carbide furnace, an oxygen-enriched air-blowing device, a tube-shell thermostatic reactor, a fixed bed tubular reactor, a fluidized bed reactor, an acetylene generator having a heat exchanger, a fixed bed reactor and a polymerization reactor, The present invention has the advantages of not only removing the dependence on oil resources during the production of polyvinyl chlorides, but also totally eliminating the mercury pollution.