[Objective] With global warming and increased occurrences of heavy precipitation, the frequency of landslide mudflow disasters in the Pisha sandstone area will increase significantly. Understanding how water-soil interaction affect the loosening and deformation of fragile soils, ultimately leading to mudflow development, is a crucial scientific question in the evolutionary process. [Methods] This study focuses on investigating the rheological properties of Pisha sandstone (PS) slurry using a rheological method that involves dynamic oscillatory shear. The primary objective is to examine the liquefaction process and initial rheological properties of PS slurry. [Results] (1) With the increase of shear strain, the energy storage modulus (G') and loss modulus (G″) of the four PS slurries decreased and exhibited strain thinning characteristics. (2) In the samples with lower water content (w<50%), the stress and strain in the linear viscoelastic region (LVE) of purple and brown PS slurries were larger than red and white PS slurries. In the samples with higher water content (w≥50%), the stress and strain at the flow point of red and white PS slurries were larger than purple and brown PS slurries. (3) With increasing water content, G' and G″ of the four PS slurries decreased, and the stress and strain in the LVE decreased. [Conclusion] Fine particles could increase the shear strength and elasticity of the slurry in the LVE, but the fine-grained slurry was more affected by the moisture content, and the ability of the slurry structure to destroy and resist deformation was weakened immediately after the addition of water, while the phase transition was more likely to occur. The presence of coarse particles increased the extent of the elastic dominance of the nonlinear viscoelastic region and hindered the phase transition of the slurry. The results of the study can provide scientific basis for further mudflow research and disaster control in the Pisha sandstone area.