[Objective] The mechanisms through which seasonal freeze-thaw cycles, coupled with initial water content, attenuate the collapsibility of Ili loess were revealed, and a quantitative relationship between microstructural reconfiguration and macroscopic collapsibility variations was established, in order to provide a theoretical basis for prevention and control of loess landslides in seasonally frozen soil regions. [Methods] Freezethaw cycling tests were performed on samples with different initial water contents and cycle numbers, accompanied by laboratory collapsibility tests and scanning electron microscope(SEM) observations. Image and statistics-based analyses were conducted to quantitatively characterize microscopic parameters such as pore size distribution, directional frequency, pore abundance, and pore fractal dimension. Correlations between these parameters and the collapsibility coefficient were established, forming an integrated macro-micro analytical framework. [Results] ① The collapsibility coefficient decreased significantly with an increase in freeze-thaw cycles for all water contents, and samples with lower water contents were more sensitive. For loess with a water content of 14.2%, the peak collapsibility coefficient decreased from 0.094 to 0.084 after nine cycles, a reduction of approximately 10.6%. For loess with a water content of 20.2%, the peak collapsibility coefficient decreased from 0.079 to 0.076 after nine cycles, a reduction of about 3.8%.② Freeze-thaw cycles weakened interparticle cementation and altered particle connections and arrangement, thereby driving internal structural reorganization toward a new stable state.③ The pore system underwent systematic evolution. The proportion of large pores declined, the pore-size spectrum became finer and more uniform, pore directions were re-arranged, and both pore abundance and pore fractal dimension changed accordingly.④ The microstructural statistical patterns were consistent with qualitative observations and the macroscopic evolution of collapsibility. [Conclusion] Freeze-thaw cycles reduce interparticle bonding and remodel the pore-particle structure. Consequently, the reduction of large pores and changes in fractal dimension constitutes the core mechanisms driving the macroscopic weakening of collapsibility. Based on this, a physical process model of ‘freeze-thaw → microstructural reconfiguration → collapsibility response' is established, providing theoretical support for the monitoring and prevention of loess landslides in seasonally frozen soil regions such as the Ili area.