Abstract: The compressive strength of wet concrete influenced by pore water is investigated in this paper. Pore water pressure induced by compression in the wet concrete affects the mechanical properties of concrete, but the related research is little. The magnitude of pore pressure relates with the volumetric deformation of concrete and the developing velocity of cracks. Based on fracture mechanics, the effects of pore water on the initiation of crack, the development of crack and the strength of wet concrete are analyzed. The results of this investigation indicate that the pore water decreases the friction force which baffles the development of crack and accelerates the damage of concrete, and the pore pressure acts as a wedge to the crack of concrete. The initiation stress of crack and the compressive strength of wet concrete are decreased comparing with the dry sample.