The invention discloses an earth moving device and method for deep foundation pit excavation. Ground surfaces at two side at the top of a foundation pit are respectively provided with supporting tower frames; steel wire ropes are connected between the two supporting tower frames; a first winch is arranged on the steel wire ropes; the tail end of a rolling rope of the first winch is connected with an earth moving box in a hanging mode through a hook; the ground surface at the outer side of each supporting tower frame is provided with a second winch; a rolling rope of the second winch passes through the supporting tower frames, and is fixedly connected with the first winch; the first winch places the earth moving box at the bottom of the foundation pit for earth filling; and after earth is filled fully in the earth moving box, the first winch hangs up the earth moving box, then the earth moving box is pulled close to the supporting tower frames through the second winch on the ground surface, and the earth can be moved away by using earth moving vehicles stopped out of the foundation pit. According to the earth moving device and method, for the foundation pit, especially the deep foundation pit, the earth volume can be moved safely and reliably; and meanwhile, the construction manufacturing cost also can be saved, and the construction period that the earth volume of the foundation pit is moved externally can be shortened.