Running　is　a　kind　of　high-repetitive　limb　movements,　which　can　possibly　suffer　knee-joint　and　ankle　joint　badly.　In　this　paper,　the　author　uses　advanced　instrument　of　motion　capture　to　gain　the　gait　data　of　human＇s　running　motion,　then　create　the　curve　of　motion　data　tracing　the　knee-joint　and　ankle　joint　guided　by　the　theory　of　biomechanics　and　kinesiology.　Last　we　get　the　cause　about　the　suffering　of　meniscus　and　ligament　of　knee-joint　and　ankle　joint　during　the　process　of　human＇s　running　motion.　The　result　of　research　can　apply　to　biomechanics　of　human　and　the　design　of　exerciser.