Submarine drilling machine rope coring salvaging system and method thereof

The invention discloses a submarine drilling machine rope coring salvaging system and a method thereof. The submarine drilling machine rope coring salvaging system comprises a winch, a salvaging rope,a power head frame and a salvaging device, wherein the salvaging device comprises an outer sleeve, a plug cover, a mandrel, a spring and a salvaging hook. Both ends of the outer sleeve are provided with openings, and the plug cover is assembled in the opening at the top end of the outer sleeve. The middle part of the mandrel is provide with a shaft shoulder, the bottom end is provided with a conehead which can be stuck into the salvaging hook, and the top end of the mandrel extends through the plug cover to the outer sleeve. The spring sleeves the mandrel and is positioned between the plug cover and the shaft shoulder, and the salvaging hook is assembled at the bottom end of the shell. A through hole is provided on the power head frame, and the diameter of the through hole lies between that of the mandrel and tha