Ruiguang Pagoda has the longest history. It is said that during the Three Kingdoms period Sun Quan, the king of Wu, ordered the Puji Temple constructed for a monk, Xing Kang, from the state of Kangju when he went to Suzhou in 240. In order to express his gratitude to his mother, Sun Quan built a thirteen-storey sarira pagoda inside the temple in 247. This was the earliest Buddhist pagoda in Suzhou. Because of neglect over many years the pagoda was in a state of disrepair by the Five Dynasties. In 937, during the Later Jin Dynasty, when major repairs were going on, so the legend goes, brilliant rays of five colors were seen above the pagoda, so the emperor granted that a bronze board with the inscription Rui Guang Ta (Pagoda of Auspicious Light) be hung on the pagoda, and since then the pagoda has been known as Pagoda of Auspicious Light. From 1119 to 1125, when the pagoda was again in bad shape, a wealthy man provided funds for its reconstruction. He thought thirteen storeys were too high and changed the structure to seven storeys. That is the present pagoda.
Ruiguang Pagoda is an octagonal building of 43.2 meters, built of both brick and wood. The body was composed of bricks, but the eaves, balconies and banisters were made of wood. The stone Sumeru pedestal is embellished with carved patterns. The steeple of the pagoda was broken by a strong wind in June 1879 and the pent roofs have become mined, too, but they have all been restored now.
In April 1978 many cultural relics were found in a brick recess inside the third storey of the pagoda, including two gilded bronze stupas, nine statues of Guardian of the Earth and Goddess of Mercy and other Buddhist images, more than one hundred twenty volumes of Buddhist scriptures and a pillar' inscribed with Buddha's name and scriptures. The 122.6-centimetre pillar, with pearls and precious beads and combining the art of jade sculpture, gold and silver ware, wood carving, gold tracing and carved lacquerware, is regarded as a rare treasure of extreme value. All these unearthed relics are now kept in the Suzhou Museum.