The present invention discloses a PVC floor, and a production line and preparation method thereof. The production line comprises a feeding system, an internal mixing and extruding device, a calendering laminating device, a cooling device, a tractor, and a cutting machine arranged in sequence along a material conveying direction, wherein the internal mixing and extruding device comprises an internal mixing mechanism, an extruding mechanism, and a hopper. In the production line of the present invention, materials are rapidly dispersed and plasticized by means of an internal mixing section of the internal mixing and extruding device, and the plasticized materials directly enter an extruding section through the hopper to be subjected to extruding forming, which has a good plasticizing effect, and solves the problem of a poor plasticizing effect of traditional extruders caused by forced plasticizing of a PVC rigid product without a plasticizer; in addition, the materials do not need to pass through a high-speed mixer, and the materials are directly extruded after being plasticized, thereby shortening the mixing and extruding time of the materials, reducing energy consumption, and reducing the use of a stabilizer and internal and external lubricants in a raw material formula.