The Mudou Island is situated at the north end of the Penghu Islands, only 7 km away from the Jibei Island at the south. The island is 843 m in perimeter and only 0.0244 km2 in area. It is a tiny island famous for its Mudouyu Lighthouse.

Since the waters between Mudou Island and Jibei Island are a deep water abrasion platform, submerged reefs are everywhere, even where the water is less than one meter deep, hence the numerous accounts of shipwrecks. It is said that the ancestors who lived on Jibei used to pick up floating debris from the wrecked ships. But for precisely the same reason, animals and plants under the sea can all enjoy sufficient sunlight, and people above water can also see right to the bottom of the ocean and appreciate the beautiful underwater world. For the safety of boats, a lighthouse was built on Mudou Island in 1899. A black and white-striped iron-framed lighthouse, soaring to a height of 40 meters, stands as the tallest lighthouse in East Asia.

The lighthouse is equipped with its own generators and lighthouse keepers. The basalt-composed Mudou Island still maintains its primitive landscape, with black rocks surrounding it, causing beautiful waves and giving off a sense of magnificence.

There is a shallow sand belt between Mudou Island and Jibei Island, extending hundreds of meters long and five meters wide, where the water only comes up to the knee height. Walking on the sand belt is as entertaining as walking on the sea. If you visit here, you can also see beautiful seashells, but you must be careful. If you take a speedboat from Jibei Harbor, you can see coral reef clearly along the way, with tropical fishes swimming in the water. It is truly a spectacular and beautiful sight. Another remarkable landscape of Mudou Island is the underwater tunnel. It is at the bottom of a cliff, hidden by the sea during high tide, but people can walk sideways when the tide ebbs.