The utility model discloses a test device for simulating the bending resistance of pile foundations. The test device comprises a model box, a bracket mounted at the upper part of the model box and a pile foundation bending moment capacity loading system, wherein foundation soil is accommodated in the model box; a test pile is inserted into the foundation soil; the pile foundation bending moment capacity loading system comprises a loading platform, a dowel bar fixing plate, a dowel bar structure and a pile top bearing platform; the loading platform is connected with a steel wire rope which extends upwards and then horizontally extends to the upper end of the dowel bar structure; two force-exerting rods, which are used for exerting pulling force on one side and pressing force on the other side of the test pile respectively when being driven by the steel wire rope, are arranged between the dowel bar structure and the pile top bearing platform; the upper ends of the two force-exerting rods are in rotational connection with the dowel bar structure, and the lower ends of the two force-exerting rods are fixedly connected with the pile top bearing platform. The test device can exert pure bending moment capacity on the test pile, and can be used for studying the bearing property of the pile top under the action of pure bending moment.