The invention relates to a method for manufacturing a small solder ball, in which a substrate is reusable. The invention is characterized in: firstly, the reusable substrate is prepared by means of IC manufacture process: a silicon wafer is used as a base, a metal conducting layer is sputtered from the front after heat oxidation treatment; secondly, the small solder ball is manufactured on the reusable substrate: a metal sacrificial layer is sputtered on the substrate to cover the opening of the conducting layer, thick photosensitive resist is coated and an electroplating window is photoetched, then solder is electroplated, the thick photosensitive resist is removed after electroplating, the solder is reflowed to form a solder ball, thereafter the metal sacrificial layer is corroded to be removed, so that the solder ball can drop off completely from the reusable substrate, and finally the solder ball is collected. According to the invention, the manufacturing procedure is simple and consumes small energy, the process has good controllability, the bottleneck of low productivity is overcome; the manufactured solder ball has smooth surface, good sphericity and uniform size, with the smallest grain diameter being 0.15mm.