The invention relates to a black weeding mulching film special for potatoes. The black weeding mulching film special for the potatoes is made of linear low density polyethylene, low density polyethylene, metallocene polyethylene, high density polyethylene and mulching film master batch raw materials. The mulching film master batch is made of the linear low density polyethylene, low density polyethylene, metallocene polyethylene, high density polyethylene, black master batch, dispersing agent stearic acid, dispersing agent polyethylene wax, ultraviolet radiation absorbefacient, antioxygen, herbicides, aggregate type hindered amine light stabilizer and heat preservation agent hydrotalcite raw materials. A preparation method of the black special weeding mulching film for the potatoes includes the following steps that (1) the mulching film master batch raw materials with different weight parts are sent to an automatic blender mixer, stirred evenly in a mixed mode and inspected for use; (2) the mulching film master batch raw materials with different weight parts are sent to the automatic blender mixer, stirred evenly in a mixed mode, and are subjected to automatic plasticizing extrusion in a plasticizing extrusion machine, blowing traction, slitting and rolling, inspection and warehousing. By means of the black weeding mulching film special for the potatoes, nutrient loss of the potatoes can be reduced, the utilization rate of fertilizers is improved, the service life of the black weeding mulching film special for the potatoes can reach 12 months, and the black weeding mulching film special for the potatoes can be effectively recycled after being used.