Due to the intergranular cementation of free iron oxides （FIOs）， granite residual soils （GRS） are highly structural and water-sensitive. Therefore GRS exhibits structural disintegration and reorganization and complex shear deformation properties when subjected to dissolution of the intergranular cemented oxides under repeated drying and wetting （D-W） cycles. In order to further investigate the structural changes caused by the dissolution of the cement FIOs under D-W cycles and its effect on the weakness in mechanical properties of GRS， a series of macroscopic tests were carried out to reveal the complex mechanical behaviors of GRS under different numbers of D-W cycles （0， 1， 2， 4）. The experimental results show that the stress-strain relationship of GRS gradually transforms from a weak strain-hardening type into a strain-softened state with the increase in the number of D-W cycles. The microscopic analysis indicates that the FIOs lead to the cementation of soil particles into soil aggregates. However， the content of FIOs shows a decreasing trend but finally tends to be a stable value after the D-W cycles. In addition， the particle size distribution （PSD） curve exhibits an evident bimodal peak， then changes to a single peak curve after the D-W cycles or the removal of FIOs. The repeated D-W cycles weaken the cementation structural properties of the GRS， resulting in the obvious softening characteristics of the soil. During the shear process， GRS first displays shear shrinkage properties， followed by the trend of dilatancy. With an increasing number of D-W cycles， the effective cohesion of the GRS gradually decreases， but the effective internal friction angle shows a trend of increase. The complicated mechanical properties of GRS are characterized by coupling effects among the irreversible volume shrinkage， the variation of collodion content， and the development of microcracks.