Abstract: The weakly cemented sandstone in the western mining area exhibits unique properties such as weak diagenesis, poor cementation (argillaceous cementation), low mechanical strength, and easy to softening, which are closely related to stress conditions and argillaceous contents. To investigate the impact of varying stress conditions and argillaceous contents on the deformation and strength characteristics of weakly cemented sandstone, conventional triaxial compression tests are conducted on four groups of sandstone samples with different levels of argillaceous content based on X-ray diffraction test analysis results. Results indicate that: the peak axial strain, elastic modulus, and Poisson’s ratio of weakly cemented sandstone increase significantly in a linear form with the increase of confining pressure, whereas the elastic modulus decreases significantly in a linear form with the increase of argillaceous content, moreover, increased confining pressure mitigates the effect of argillaceous content on the peak axial strain, elastic modulus, and Poisson’s ratio; both the peak strength and residual strength of weakly cemented sandstone increase significantly in a linear form with the increase of confining pressure, whereas the peak strength, residual strength, and cohesion decrease significantly in a linear form with the increase of argillaceous content, moreover, increased confining pressure mitigates the weakening effect of argillaceous content on mechanical strength; with the increase of confining pressure or argillaceous content, the failure mode of weakly cemented sandstone samples shifts from brittle shear failure to ductile tensile failure.