Abstract: The success of Three Sus was not an accident; rather, it was partly attributed to the political and cultural environment then. The political environment was favorable in Renzong Period of Song Dynasty when the emperor was open-minded, thirsting for talents, when the prominent officials at all levels were of high integrity, insightful and cherished talents. Three Sus were discovered, supported, protected by them and finally their fame rose swiftly in the capital from the remote western Sichuan. Meanwhile, the Ancient Prose Movement promoted by Ouyang Xiu built the best cultural environment for them, in which they became the nucleus. Thus, in such political and cultural environment was their pursuit for innovation and high achievements maximized.