The invention relates to an artificial island and a sinking method and a floating method thereof, the artificial island comprises a
caisson module, and the
caisson module comprises a box body provided with a containing cavity; the vertical
pile is connected with the bottom of the box body; the liquid passing
assembly communicates with the containing cavity and is configured to enable the box body and the vertical
pile to sink when liquid is injected into the containing cavity, so that the vertical
pile is inserted into the
seabed; and when the liquid in the accommodating cavity is discharged, the box body and the vertical pile float upwards. And the
caisson modules can be subjected to unified
modular construction on the land, so that the construction period on the sea is shortened. A tugboat is adopted to transfer the caisson module to a preset sea area, the liquid passing
assembly can inject liquid into the containing cavity, the box body containing water drives the vertical pile to sink till the vertical pile is inserted into the
seabed, and floating of the caisson module can be avoided through the acting force between the vertical pile and the
seabed. The box body has certain structural strength, the stability of the worker island foundation is guaranteed, the space in the containing cavity is filled with water, a large amount of earth and stone does not need to be used for filling a preset sea area, and the offshore
engineering amount is reduced.