Su-ao Lighthouse, built in 1927, is located on the hilltop back at Beifangao near Su-ao Harbor in Yilan. The lighthouse is a white tetragonal building made of concrete. The lighthouse was originally equipped with the fourth-class acetylene flash lamp, which flashed in white twice consecutively every seven seconds with 1,000,000 candlepower light. The lighthouse was also installed with red arc-light signals to identify the positions of reefs at Sansiantai near the harbor.

　　The lighthouse was bombarded during the World War II, and then stopped service. After the Recovery of Taiwan, the lighthouse was renovated in 1949, and installed with the sixth-class acetylene flash lamp, which flashed once every seven seconds. The lighthouse was re-equipped with the electric lamp in 1953. In 1954, the lighthouse was refitted with the fifth-class electric lamp, which flashed every second with 15,000 candlepower of white light and 2,600 candlepower of red light.

　　One power generator room and dorms were built and guarded in the mountainside of front-mountain area of Beifangao in 1966.

　　In 1969, the lighthouse was re-equipped with the fourth-class electric light, which featured higher lighting power of 21,000 candlepower of white light and 3,600 candlepower of red light.

　　Radar beacons was installed in 1985.

　　Height of Lighthouse: 7.9 meters

　　Height of Light (above H.W.): 56.1 meters

　　Nominal range: white light: 16 nautical miles, red light: 12 nautical miles