Abstract: Collapses controlled by joints and freezing-thawing weathering widely occur in the Taxian area of Xinjiang. In order to reveal the mechanisms of freezing-thawing deterioration of rock mass and collapse formation, samples of gneiss are examined from the aspects of microstructure and physico-mechanical characteristics in freezing-thawing cyclic tests of different times in the dry and fully saturated states. The research results show that the microstructural deterioration of gneiss, which is caused by peeling of internal particle and propagation of microcrack, reduces the strength and intensifies weathering of rock mass. The long-term freezing-thawing cyclic effect may causes collapses, which provide source for debris flows.