Provided are an equipment hoisting transitional supporting platform on an ultrahigh building floor and a construction method thereof. The construction method comprises the steps that 1, construction of cantilever steel beams is conducted; 2, profiled steel sheets of a floor slab are laid, and the profiled steel sheets are laid on the steel beams; 3, a support frame is designed; 4, the support frame is manufactured; 5, the support frame is hoisted in place; 6, concrete of the floor slab is poured; 7, equipment hoisting is conducted for the primary in-place mode; and 8, the equipment secondary in-place mode is achieved, so far the equipment is in place, and construction is completed. According to the equipment hoisting transitional supporting platform on the ultrahigh building floor and the construction method thereof, the technical problems that by adopting a traditional hoisting mode that a hole is reserved or civil construction structures, such as a large-size unloading platform, are manufactured, the dangerousness is high, both the time and the cost are consumed, and the traditional hoisting mode can have an effect on a main body structure are solved.