The invention discloses a power supplying and driving device and method for an ocean monitoring device. By means of the power supplying and driving device and method for the ocean monitoring device, power can be supplied to the ocean monitoring device, meanwhile, driving force can be provided for the ocean monitoring device, and the ocean monitoring device is simple, convenient to use, high in reliability, low in cost, free of pollution and long in service life. The characteristic that a solid-liquid phase change material conducts phase changes along with temperature changes is utilized, a phase change cylinder containing the solid-liquid phase change material is in direct contact with seawater, the phase change cylinder can be solidified and melted repeatedly in the floating and submerging process of the ocean monitoring device, the ocean temperature difference energy is converted into the size change, energy is charged to an accumulator, the accumulator is controlled to release the energy and change the size of an external oil bag so as to drive the ocean monitoring device to vertically move through a series of pipelines and valves, a hydraulic motor is driven to rotate to drive a generator to generate electricity, and power is supplied to a control system and a measuring device of the ocean monitoring device.