Most of the foot deformities relate with the arch collapse or instability, especially the medial longitudinal one. Though the function of the plantar fascia to the arch height has been investigated by some authors, the other plantar ligaments‘ effects are still unclear. The purpose of this study is to explore the roles of the plantar soft tissues in the foot arch biomechanics, including the plantar fascia, spring ligament complex, short plantar ligament and long plantar ligament through normal adult fresh frozen specimens in different injured condition. Also, a three-dimensional finite element model of a normal left foot was developed, which was comprising most joints of the foot and consisted of bone segments, major ligaments and plantar soft tissue. The validity of the three-dimensional finite element model was verified by comparing results with experimentally measured data via the displacements and Von-mise stress of each bone segments. These intrinsic ligaments of the foot arch were sectioned in different sequences in the cadaveric experiment, which simulated the different pathologic situations of the plantar ligaments injury and described the bone segments displacement and stress distribution.