Gusao Pagoda stands on Baogai Mountain on the seacoast south of Quanzhou, facing the Taiwan Straits. Ships began to take the pagoda as a navigation mark a long time ago.

It was said that at the foot of Baogai Mountain lived a couple and the husband's younger sister. They cared for one another and lived peacefully, tilling the land and fishing. But one year there was a drought. No grain was harvested and no fish were caught. However, the landlord and local officials asked for land rent and tax payments just the same. So the family decided that the husband should seek his fortune overseas. They planned to reunite in three years. After the husband left, his wife and sister had a hard time and longed for his early return. Every day they went to the top of Baogai Mountain to look for returning ships. To see farther, the sisters-in-law carried a rock to the top every day, thus forming a pagoda. The husband worked hard overseas and earned much money. After three years he returned to his hometown in a boat he had made himself. One day the sisters-in-law were standing on the mountaintop as usual and saw a sail coming nearer. Standing on the boat was the husband. His wife and sister were overjoyed. However, a scoundrel had followed them and, seeing the boat, pretended to go and greet the husband in a boat. When the two boats drew near, the scoundrel hit the husband with a cudgel and pushed him into the water. He not only seized the husband's money, but also forced the sisters to marry him. They pretended to agree, but said they must first climb the pagoda and look into the distance. When all three reached the top, the sisters pushed the scoundrel down to the sea, where he drowned. Then they sailed away in the boat the husband had brought back. To commemorate them people call the pagoda Gusao (Sisters-in-law) Pagoda.

The pagoda is also called Wanshou Pagoda because the lintel of the door on the second floor is inscribed with that name, which may be the pagoda's formal name.

Gusao Pagoda, modeled after wooden structures though built entirely of stone blocks, is octagonal, with a diameter of 20 meters, a height of 21.65 meters and covering an area of more than 300 square meters. All five storeys have pent roofs. On the west side of the first storey there is a portico. The other storeys each have two doorways. The sections of the corner pillars are in the shape of plum blossoms and above the pillars are huge brackets. The pent roofs of each storey are formed by two tiers of stone covered by stone slabs. Stairs lead from the first storey to the other storeys, and around the main body of the pagoda are stone banisters and verandas, enabling people to go to the top of the pagoda and enjoy the view of sea and mountain.

As winds coming from the sea are very strong, the design of the pagoda is different from that of other pagodas. The exterior of the pagoda tapers greatly from the bottom to the top, making it very sturdy; even typhoons can do no harm to it. This is one reason it has lasted for some thousand years.