The utility model relates to a testing and loading device for the bearing capacity of a pile foundation. Symmetric larger holes which are arranged on the top cover plate and the bottom cover plate of a load box between jacks enable concrete to pass through smoothly and ensure the mass of the concrete of a pile body on and under the load box. Guide round steel bars arranged between the main reinforced bars of a reinforcement cage and the top cover plate of the load box ensure ducts to pass through the load box smoothly. The duct holes in the center of the top cover plate of the load box are made round taper holes with the big end down to prevent the concrete from hanging in the ducts during concrete perfusion of an ultra-long pile. The testing and loading device is easy to be manufactured and assembled with simple structural design.