Polydactyly is more common among hand and foot deformities, and its causes may be related to genetic history, physical condition of both parents during pregnancy preparation, maternal health and external stimuli. If there is no precedent of hand-foot deformity in both parents’ families, parents can pay more attention to the health condition and external environment when preparing for the second baby, and stay away from second-hand smoke, formaldehyde and other harmful substances, which can effectively reduce the chances of the second baby having polydactyly. If the second child is born with polydactyly, parents do not have to worry too much about it, as we can now correct polydactyly through polydactyly surgery, which can achieve both shape and function.