Abstract: In the triaxial tests of coarse-grained soil, the geotextile is often used to wrap the specimen used to prevent the rubber membrane from being punctured. This method is widely applied to the practical works. Therefore, the testing analysis of the influences of the geotextile on the strength and deformation behaviors of the coarse-grained soil is carried out in this study. The coarse-grained soil wrapped by the geotextile and that without the geotextile are subjected to a series of drained triaxial compression tests using medium size specimens. The experimental analysis results show that the strength (σ₁-σ₃)_f of the specimens wrapped by the geotextile is larger than that of the normal specimens without the geotextile under the same confining pressure, and the increment ratio is decreasing with the increase of the confining pressure. In addition, the relationships between the increment ratio and the confining pressure can be expressed by a power function. The linear strength index of the specimens wrapped by the geotextile, cohesionc, is 1.8 times than that of the normal specimens without the geotextile, and the internal friction angle φ is reduced by 1.8°. The nonlinear strength index of the specimens wrapped by the geotextile, φ₀, is 1.07 times that of the normal specimens without the geotextile, while Δφ is increased by 5.5°. The volumetric strain and the lateral strain of the specimens wrapped by the geotextile are larger than those of the normal specimens without the geotextile under the same confining pressure. The volumetric strain difference and the lateral strain difference of the specimens wrapped by the geotextile and the normal specimens without the geotextile are less affected by the confining pressure, which is a constant independent of the confining pressure.