The invention discloses a six-degree-of-freedom offshore wave compensation multipurpose boat and a wave compensation method thereof, the wave compensation multipurpose boat comprises a navigation boat body, a
deck and a six-degree-of-freedom electric wave compensation
system, and the
deck is a whole needing wave compensation; the six-degree-of-freedom electric wave compensation
system is a connecting part of a navigation boat body and a
deck and is composed of an electric cylinder and other components or auxiliary accessories necessary for electric wave compensation. By measuring motion attitude values of rolling, pitching, heaving, swaying, surging and yawing of a ship body, compensation values of rolling, pitching, heaving, swaying, surging and yawing are calculated according to an inverse solution
algorithm of wave compensation values, all
servo electric cylinders are controlled to act, and six-degree-of-freedom compensation of an upper deck is achieved. Wave compensation can be carried out on the whole deck, the influence of
waves on a boat body is reduced, six-degree-of-freedom grouping is controlled through the layered wave compensation platform structure, and more
working space is provided for the wave compensation structure.