Objective To explore dynamic characteristics of the gait for the elderly with different fall risks before and after obstacle crossing. Methods Twenty-seven elderly people in community were graded as fall risk by using the time up and go test and five-time sit to stand test. The plantar pressure parameters of the elderly before and after obstacle crossing were measured and analyzed by foot pressure measurement system. Results There was no significant difference in the characteristic value of bimodal curve of overall plantar pressure between the high and low fall risk groups before and after obstacle crossing(P>0.05). The center of pressure (COP) trajectory in X direction of high fall risk group after obstacle crossing was significantly greater than that of low fall risk group (P<0.05). Before obstacle crossing, the peak pressure of the 3rd metatarsal of supporting foot was higher in high fall risk group than that in low fall risk group (P<0.05). After obstacle crossing, the peak pressure of the 1st phalanx of supporting foot was significantly lower than that in high fall risk group (P<0.05), while the lateral heel impulse in high fall risk group was significantly larger than that in low fall risk group (P<0.05).The distribution patterns of contact area of the foot for the elderly in two groups before and after obstacle crossing were basically the same, and there was no significant difference in contact area of each plantar region (P>0.05). Conclusions The support time of the elderly with high fall risk is longer than that of the elderly with low fall risk during obstacle crossing, the peak pressure of plantar metatarsal region of the crossing leg increases, and the plantar COP curve shows asymmetry, with an increase in transverse range of the coronal plane. In clinical evaluation, plantar pressure characteristics of people with fall risks during obstacle crossing should be focused on.