Gravity column sampler is the bottom of the sea sampling equipment, suitable for the whole ocean and estuary estuary sediment sampling. A sample available is 6.5 cm in diameter, length of 1.5-3 m (depending on the sediment properties change) samples, sample including bottom sediments and sediment in overlying water, can fully meet the ocean engineering geology, biology, chemistry, geotechnical exploration research need and the change of ecological environment project, is a Marine and estuary harbour bottom sediment investigation and research of the necessary equipment.