An integrative deep draft floating production platform with unconditional stability and an offshore installation method thereof are disclosed. The platform comprises an ring ballast tank at the bottom, some columns with small cross sections, an ring buoyancy tank at the middle part, some columns with large cross sections, and an upper drilling equipment and oil gas processing module. The ballast tank adopts a permanently fixed ballast, and the tank is internally filled with weights to ensure that the center of buoyancy of the platform is higher than the center of gravity. The drilling equipment and oil gas processing module is installed in the construction site, and the platform is transported to the installation site by a dry tow or wet tow as a whole and then is installed. The platform can be applied to deepwater oil and gas exploitation under harsh marine environment.