Disclosed are a sinking-floating control device and a multi-working-condition sea cucumber search fishing device capable of sinking and floating. The multi-working-condition sea cucumber search fishing device capable of sinking and floating comprises open type buoys, a high pressure gas cylinder, control valves, a chassis framework, electric wheels, a driven wheel, a steering vertical shaft, a tail vane, a propeller, motors, a mechanical arm, a suction tube, a camera, warehouse and an umbilical cable. The top of each buoy is provided with the normally closed type control valve, and the bottom of the buoy is provided with a normally open opening; the high pressure gas cylinder is connected with a tee joint, one opening of the tee joint is normally closed, the other opening of the tee joint is firstly connected with the normally closed type control valve and then is connected with a high pressure air duct continuously; the other end of the high pressure air duct is communicated with the corresponding buoy. Every motor and the camera are all connected with the umbilical cable through wires. The suction tube is attached to the mechanical arm, and the front end of the mechanical arm is provided with the camera and a clamp. The multi-working-condition sea cucumber search fishing device capable of sinking and floating is multifunctional and has strong environmental suitability, can achieve the floating movement, searching and fishing by sinking to the bottom, and sea floor travelling of the fishing device; can adapt to multiple seabed environments of mud, sand, reef, rock and the like, and can suck and catching sea floor objects such as sea cucumbers quickly, stably and accurately both in still water and running water.