Based　on　the　fatigue　damage　tests　of　rock-soil　materials,　a　new　mathematic　model　of　the　fatigue　damage　of　rock-soil　material　is　proposed　by　using　system　analysis　method　and　signal　process　technique　and　the　parameter　of　fatigue　damage　is　defined　by　means　of　bulk　tests.　The　results　show　that　damage　parameter　defined　is　susceptible　and　can　trace　effectively　damage　process　of　the　samples.　The　damage　process　is　divided　into　crack　pullulating,　crack　expanding　and　crack　high-speed　expanding　stage.　Moreover,　the　relation　curve　between　damage　parameter　and　cycle　times　shows　that　the　fatigue　age　of　cement　samples　which　has　the　same　adding　cement　ratio　and　age　is　different.　The　damage　process　of　the　sandstones　which　have　different　components　is　not　completely　similar,　even　though　their　fatigue　age　is　the　same.