[Objective] The multi-level collapsibility of loess was investigated and the way of loess collapsibility deformation was studied at the microscale in order to provide a scientific basis for the study of loess collapsible deformation mechanism.[Methods] We designed and conducted a indoor cyclic collapsibility test, to observe the micro-structure of the same samples under repeated humidification and dehumidification processes. The collapsibility data were analyzed and the scanning electron microscopy images were compared.[Results] The collapsibility data showed that after the loess reached the first collapsibility and water removal stability, adding water into the device would cause the deformation of the sample again. During the collapsibility process, the micro-structure undergone three deformation modes:dissolution, movement and reconstruction.[Conclusion] It is the dynamic process of destruction-reconstruction-destruction of loess structure that leads to multi-level collapsibility of loess.