The invention provides a long core water injection test simulation system. The long-core water injection test simulation system comprises a long core clamper, a pressure pump, as well as a displacement pump, a manometer and a voltage return pump, wherein the pressure pump is connected with the long core clamper, and is used for applying confining pressure and axial compressive force to the long core clamper, and the displacement pump, the manometer and the voltage return pump are connected with the long core clamper; the long core clamper comprises a clamper barrel (1) and a high-pressure-resisting rubber sleeve (2) sleeved in the clamper barrel (1); the high-pressure-resisting rubber sleeve comprises a wall (21), an inner cavity (23) positioned in the wall (21) and ports positioned at two ends of the inner cavity (23); and the inner cavity (23) is vertical-tube-shaped, and the inner diameters of the ports at the two ends are equal to the inner diameter in the middle of the inner cavity (23). The long core water injection test simulation system can be used for performing axial detection at multiple pressure monitoring points on long cores, has a small end surface effect, small dead volume, large static confining pressure and small measurement error.