A preparing method for cadmium sulfide quantum wire, in particular a method for preparing cadmium sulfide quantum wire by template is provided, which pertains to the technical field of nanometer material preparation. Wherein, alumina containing micropore array is taken as a template, the diameter and depth of the micropore is 8-20 nm and 2-3 micrometer respectively; DC electro deposition is used to prepare cadmium sulfide quantum wire with adjustable size in the micropore array. The method can effectively control the size of the cadmium sulfide quantum wire, so that the wire is of quantum-limiting effect, and hence the width of the forbidden band can be adjusted by the quantum-limiting effect, so that the absorption coefficient of the cadmium sulfide is bigger than that of the substrate material; the preparing method makes the wires arrange in order way in the alumina template having micropore array, the quantum wires are separated each other and can be positioned accurately. The preparing method is especially suitable for preparing cadmium sulfide quantum wire.