Abstract: The concrete samples under different initial pore water pressures were tested with different strain rates by a 10 MN large multifunctional hydraulic servo static and dynamic triaxial test equipment. The testing results show that: under confining pressure, changes of internal pore-water pressure can be divided into three phases: rapid, slow and stabilizing phases. Under the conditions of different strain rates, the peak stress of concrete increases gradually along with the increase of the initial pore water pressure and a high strain rate improves the influence of the initial pore water pressures on the peak stress of concrete; and under different initial pore water pressures, the peak stress of concrete increases with the increase of the strain rate. According to the testing data, based on Weibull statistical theory, a rate-dependent constitutive model for concrete is developed. The stress-strain curves of concrete with different pore water pressures under the confining water pressure are described by the model established, and the fitting results are good. The model can be used to describe the stress-strain curves and the damage of concrete under different working conditions.