In order to evaluate the bearing capacity of the Kezihe River aqueduct structure, Water filled loading test was carried out. Based on the real time monitoring of the deflection value in the midspan of the loading process and the residual deflection value after unloading, the variation of the deflection value with the upgrading of the load in the loading process was analyzed, the loading level and the load stabilization time was determined, the working state of the structure under different loads was clarified, and the structural bearing capacity was evaluated using structural bearing capacity evaluation indices. The results show that the water filled loading test was carried out in six stages, and 30 min of load stabilization time would suffice according to the test requirements. The measured deflection value of each beam rose with the increase of the load and reached the maximum value of 3.40 mm (longitudinal beam), 2.53 mm (left beam) and 2.35 mm (right beam) when the aqueduct was at full water level. The measured deflection had a significant linear relationship with the load at all stages, with the linear correlation coefficient reaching 95% or above, indicating that the structure was in a linear elastic working state. The values of the maximum deflection, relative residual deflection and deflection calibration coefficient of the structural bearing capacity evaluation indices were all lower than the specified maximum values in the specification. Compared with similar projects, the Kezihe River aqueduct structure has good bearing capacity.