The invention discloses a power generation system formed with buoyancy and relates to the technical field of buoyancy type power generation systems. The power generation system comprises an airbag arranged rotationally along the longitudinal circumference, and the airbag is in a bulge form during rising and is in a flat form during falling. Through the power generation system, the problems that according to a buoyancy power generation system in the traditional art, how continuous power generation is achieved by fully utilizing the motion stroke of a floating body is ignored, the characteristics of the floating body cannot be fully utilized to generate additional power, and the ratio of driving consumed energy to the power generation quantity is ignored are solved.