Deep layer sampling system and method of coarse sand riverbed of sediment-laden river

The invention discloses a deep layer sampling system of a coarse sand riverbed of a sediment-laden river. The system comprises an underwater sampling device comprising a vibrating compaction mechanism, a support framework, a cradle head, a drilling mechanism and an underwater communication electric cable, wherein the support framework comprises a base and four support legs; the drilling mechanism comprises a drilling motor, a drilling pipe and a sampling pipe, and is installed on the cradle head; the vibrating compaction mechanism is installed o the cradle head; the cradle head is connected with the base of the support framework by a screw mechanism; the screw mechanism is driven by a servo motor. According to the invention, the support legs of the support frame are inserted into the sediment layer in the bottom of a river by adopting a vibrating compaction mode; the integral stability of the drilling process is ensured depending on the gravity of the sampling device and the viscous resistance to the support