In order to solve the shortcomings of low accuracy and low efficiency of artificial arch index measurement. It is proposed to use the dynamic information of the plantar support surface to measure the arch index. Obtain the trajectory of the ground reaction force on the heel, the outside of the sole, and the inside of the sole from the developed distributed force plate. The area SΔ ABC formed by the three points is used to express the support surface information. The mean value MSΔ ABC of SΔ ABC for five 30-second bipedal standing posture tasks was obtained as a key parameter of the foot arch height index (FAI). The combined caliper arch height index measurement system (AHIMS) was used to classify the foot arch types of 30 subjects, and the FAI value was analyzed by variance. The results showed that the FAI value gradually increased from the low arch group, the normal foot group to the high arch group. There was a significant difference between the low arch group and the high arch group (P<0. 001), and between the normal foot and the high arch group (P< 0. 01). The results show that the dynamic information SΔ ABC of the plantar support surface can express the arch height index of the foot.