In order to study the full-range failure process of bar-wrapped cylinder concrete pressure pipe (BCCP) under internal water pressure, tests on three prototype BCCPs with different diameters were designed. Annular strain gauges were arranged on the cylinder, steel bar, and concrete protective cover of the BCCP with a diameter of 1 800 mm, and the force response of each part under the action of internal water pressure was obtained by increasing the applied internal water pressure to 2.5 MPa step by step. It was found that the load-bearing process of BCCP from prestressing to ultimate failure could be divided into 5 stages. First, the concrete core was subjected to the force of the prestressed steel bar without protective cover. After being wrapped, the core formed by cylinder and concrete was subjected to an initial pre-compression stress. Second, the whole pipe was in the elastic stage before the protective cover cracked. It corresponded to the stage when the internal water pressure in the test was less than 1.5 MPa, and the core was still under pressure, while the prestressed steel bar and the outer concrete protective cover were under tension. Third, the concrete core was in the elastic stage after the protective cover cracked. When the internal water pressure arrived at 1.6 MPa, the cover reached the tensile strength and began to crack, and the concrete core also transformed from the initial compression to tension slowly and remained in elastic state. Fourth, the cylinder and the steel bar were in the elastic stage of tension after the concrete core cracked. As the water pressure arrived at 2.2 MPa, the concrete core cracked radially, but the stress of cylinder and bars still increased steadily with the internal water pressure. Fifth, the pipe was completely destroyed. The cylinder and the steel bars reached the ultimate yield strength, and the whole pipe lost its bearing capacity. The research results could provide basis for the popularization and application of BCCP in water transfer engineering and the formulation of relevant standards.