The invention discloses a preparation method of waterborne polyurethane synthetic leather Bayse and applications of the waterborne polyurethane synthetic leather Bayse, belonging to the technical fields of the synthetic leather and the preparation method. The preparation method comprises the following steps: (1) preparing a bottom cloth; (2) impregnating the bottom cloth, wherein, the impregnation prescription contains the following components in parts by weight: 100 parts of water and 1-10 parts of metal nitrade, and the liquid rate of the impregnated bottom cloth is 10-30%; (3) heating, ironing, pressing, polishing and baking the bottom cloth after impregnating; (4) coating a waterborne polyurethane foaming layer on the bottom cloth after baking; (5) obtaining the synthetic leather Bayse after common baking, pressing and polishing. According to the preparation method, the defects of fussy operation, heavy pollution and drying difficulty in the existing preparation process of the waterborne polyurethane synthetic leather Bayse are overcome; one-time impregnation prescription and process, which are free of pollution, low in liquid rate after impregnation, and easy to bake are provided; meanwhile, a synthetic leather product taking the waterborne polyurethane synthetic leather Bayse as a base cloth is also provided; the preparation method is high in efficiency, and the obtained product is good in performance.