Under the action of saturated water，the rock foundation of the port in the red bed area weakens in the anti-deformation and bearing capacity，which affects the stability of the port foundation. To explore the influence of water saturation on mechanical properties of rocks in red bed area，we take sandstone，argillaceous sandstone，and mudstone as research objects to conduct the water absorption measurement，Brazilian splitting，as well as uniaxial and triaxial compression tests. The results show that mudstone has the strongest water absorption，with an average of 0.505%. The average water absorption of argillaceous sandstone and sandstone is 0.435% and 0.414% respectively. The Poisson’s ratio of the three kinds of rocks increases after water saturation，indicating that the circumferential deformation is more sensitive than the axial deformation，and the volume expansion is more significant after water saturation. The tensile strength and the uniaxial and triaxial compressive strength of rock show different degrees of attenuation after saturation. The research results may serve as reference for the study on mechanical properties of water saturated rock and the bearing capacity of port foundation in the red bed area.