The invention discloses a well-hole car. A supporting elevation device is arranged between two lateral support beams and a large chassis so that the lateral support beams can be elevated or dropped for an appropriate distance relative to the large chassis in the vertical direction. The invention also discloses an unloading method for the well-hole car. When cargoes are unloaded, the supporting elevation device is used for supporting up the lateral support beams and cargoes to an appropriate height, and a supporting part can be arranged between the cargoes and the floor or between rail surfaces just at the moment. Then the lateral support beams and the cargoes supported thereon are lowered till the articles are completely supported by the supporting part so that the lateral support beams are separated from the cargoes. Next, a small hoisting apparatus can be used for disassembling the lateral support beams, and the cargoes are horizontally moved away, so as to finish the unloading, without a large hoisting apparatus provided in a unloading site; and not only the human labor and physical resources are saved, but also the application scope of the well-hole car is expanded.