The invention relates to a mould and method for laying granular impermeable materials. The mould comprises a rectangular frame, a base plate and at least two limiting blocks, wherein a hole is formed in the base plate, the limiting blocks are arranged on the outer sides of two adjacent edges of the frame, the surface of the frame and the surface of the base plate are sequentially coated with a binder layer and a film-coated quartz sand layer, and the surface of the frame and the surface of the base plate are each of a wavy structure. The mould can be used for laying the granular impermeable materials rapidly and stably and has the advantages of being easy and convenient to use and good in effect, construction efficiency is greatly improved, manpower resources and material resources are saved, and time cost is reduced; meanwhile, due to the fact that film-coated quartz sand has a good hydrophobic property, the interfacial effect between the film-coated quartz sand and the granular impermeable materials is weak, and water can not permeate through gaps between the mould and the granular impermeable materials.