Abstract: To investigate the effects of different arch-support structures on plantar pressure distribution, a scanner was used to obtain three weight-bearing conditions (full-weight-bearing,semi-weight-bearing,and non-weight-bearing) foot models of nine young women with flat feet. Three types of arch-support insoles (Type I, Type II, and Type III) and one type of non-support insole were customized; the plantar pressure test system was used to compare the distribution of contact time and plantar pressure distribution characteristics of the three types of arch-support insoles during the stance phase of gait of flat feet. Subjective ratings including static comfort and dynamic comfort were assessed for each participant. The results showed that compared with unsupported insoles, type II and type III insoles significantly reduced the total contact time during the stance phase (P=0.002 and P=0.026, respectively); all three types of arch-support insoles shifted the COP trajectory medially during the stance phase, and the shifting increased with the increase of the height of the supportive structure. The appropriate arch support insoles can optimize the contact time and COP trajectory during the stance phase, which provides a theoretical basis for the design of personalized orthopedic insoles.