Based on the permeability test and scanning electron microscope (SEM) test of textile reinforced concrete (TRC) specimens under pressure water, the effects of different concrete water-cement ratios and fiber number of per bundle on the impermeability and internal mesostructure of TRC specimens were explored. The results show that, moisture migrates along the interface between concrete matrix and longitudinal fiber bundle under pressure water and the impermeability of TRC specimens decreases with the increase of water-cement ratio and fiber number of per bundle. Furthermore, SEM test shows that there are annular cracks at the interface between concrete matrix and fiber bundle, and the crack width increases with the increase of water-cement ratio and fiber number of per bundle. Based on the concentric circular slit theory, the impermeability calculation model of TRC specimen under pressure water is established, and the calculated results are in good agreement with the experimental values.