Caisson and underwater maintenance device

The invention relates to the field of underwater operation, in particular to a caisson and an underwater maintenance device.The caisson comprises a box body with an opening in the lower portion, an inner frame and a pressing mechanism, the inner frame is arranged in the box body, a containing space is defined by the inner frame and the side wall of the lower portion of the box body, a sealing assembly is arranged in the containing space, and the pressing mechanism is arranged above the sealing assembly; pressure far away from the box body is applied to the sealing assembly. The box has the advantages that the containing space formed by the inner frame and the side wall of the opening is beneficial to forming a sealed space between the interior of the box body and a damaged part, and workers can conveniently work and maintain the box; the sealing assembly can be attached to the damaged part under the action of the pressing mechanism so as to fill a gap between the containing space and the damaged part. By adju