A method of forming a layering structure of plastic flooring comprising steps of: A. forming a substrate by using an extruder so as to one-piece extrusion form the substrate including at least two sheets, wherein the at least two sheets are a first sheet and a second sheet which stack together; B. delivering a printing layer, wherein the printing layer has patterns printed thereon and is delivered to a roller unit by using a first rolling mechanism and a first pressing mechanism; C. conveying a abrasion resistant layer, wherein the abrasion resistant layer conveyed to the roller unit by way of a second rolling mechanism and a second pressing mechanism of a rolling conveyor; D. roll pressing the substrate, the printing layer, and the abrasion resistant layer together by way of the roller unit so as to form a plastic flooring, wherein in step A, the substrate includes three sheets (111, 112, 113) which are one-piece extrusion formed by using an extruder having a first material feeder, a second material feeder and a third material feeder, wherein a material distributor is configured to distribute a material into the first material feeder, the second material feeder and the third material feeder so that three sheets (111, 1112, 113) forms the substrate; and steps B, C and D are carried out using a roller unit that includes a first roller, a second roller, a third roller, two fourth rollers, and a support frame, wherein the first roller is fixed on an end of the support frame, the second roller is located on the first roller, the third roller is disposed beside the first roller and the second roller, and the two fourth rollers are secured beside the third roller opposite to the first roller and the second roller, wherein the step D includes a first sub-step D1 in which the substrate is guided between the first roller and the second roller and is guided to the third roller via a first guide roller; the step D includes a second sub-step D2 in which the printing layer is guided to the third roller via a guide roller and a first press roller, and the abrasion resistant layer is guided to the third roller through a third guide roller and a second press roller; the step D includes a third sub-step D3 in which the printing layer is stacked on the substrate, and the abrasion resistant layer is stacked on the printing layer 12 by using the third roller, then the substrate, the printing layer, and the abrasion resistant layer are guided to the two fourth rollers via a fourth guide roller; the step D includes a fourth sub-step D4 in which the substrate, the printing layer, and the abrasion resistant layer are rolled and pressed together by the two fourth rollers of the roller unit; and the step D includes a fifth sub-step D5 in which the plastic flooring is removed from the two fourth rollers and is cut based on required sizes. A. forming a substrate by using an extruder so as to one-piece extrusion form the substrate including at least two sheets, wherein the at least two sheets are a first sheet and a second sheet which stack together; B. delivering a printing layer, wherein the printing layer has patterns printed thereon and is delivered to a roller unit by using a first rolling mechanism and a first pressing mechanism; C. conveying a abrasion resistant layer, wherein the abrasion resistant layer conveyed to the roller unit by way of a second rolling mechanism and a second pressing mechanism of a rolling conveyor; D. roll pressing the substrate, the printing layer, and the abrasion resistant layer together by way of the roller unit so as to form a plastic flooring,