The invention provides an umbrella-shaped structure of a super/extra-high voltage alternating-current composite insulator to optimize umbrella-shaped design and increase creep distance utilization rate. The umbrella-shaped structure comprises large umbrellas and small umbrellas which are equal in diameter and are alternately arranged, and the creep coefficient of the composite insulator ranges from 3.8 to 4.2. The flashover voltage of the umbrella-shaped composite insulator at unit insulating height under a hydrophilic condition is higher than that of an umbrella-shaped composite insulator with a large umbrella and two small umbrellas for a 1000kV extra-high voltage test demonstration project, the string lengths of composite insulators in regions with different contamination degrees can be decreased to different degrees, accordingly, the size of a tower is optimized, and the manufacturing cost of a power transmission line is greatly saved.