The invention discloses a method for sharing medicine, a medicine dosing robot and a medicine share system. The method comprises the following steps that current prescription data information is controlled and received, the current prescription data information is compared with the previous prescription data information, and a comparison result is output; when the comparison result is that the medicine can be shared, whether a sharing medicine exists or not is judged according to the previous prescription data information; when the sharing medicine can be shared, a corresponding amount of themedicine is sucked from the sharing medicine according to the current prescription data information. Therefore, the medicine can be shared for a plurality of times, then the medicine can be fully used, the phenomenon of medicine waste is avoided, and the medicine dosing cost is reduced.