Abstract：The Emergence of ritual musical instruments was an important characteristic in the development of ancient China's political system, with stone chime being one of the core material representations in this process.Nevertheless, how the stone chime appeared in Southwest China has long been unclear. During the recent archaeological excavation at the sacrificial area of Sanxingdui site, nine pieces of stone chime fragments were recovered from the pit No.8. Refitting analysis confirms that they all come from the same stone chime which was made of compact silt slate with an approximately semicircular shape and a clear distinction between the front and end sides. The original stone chime is 101 cm in length and 53.5 cm in width. It has a uniform thickness of 3.3 to 3.6 cm, and the surface of both sides were polished smoothly. Trimming traces can be seen around its edge, and the upper edges of front and end were roughly polished. It is surmised that its edge was chiselled with certain metal tools. The fragments were relatively concentrated around the east and west ends of pit No.8. Most of them were buried between the layer of relatively purer clay (layer 6) and the layer of burnt ash (layer 7), implying that they were cast into the sacrificial pit during a later step of the sacrificial ceremony. The cracks on the stone chime are evenly distributed on the whole, with no visible striking point on its surface. Therefore, it probably had been broken due to falling on the ground horizontally before its fragments were cast into the pit.The stone chime from pit No.8 reflects a singular hanging system, which should be the local predecessor of the double hanging system seen on the stone chimes from Jinsha site. Meanwhile, it's by far the earliest stone chime as well as the earliest large-sized ritual musical instrument discovered in Southwest China. In comparison with contemporaneous stone chimes found at the Yinxu site of the Central Plain, the Sanxingdui stone chime shows no inferior in either sizeor craftsmanship. Given that no earlier and more primitive prototype of stone chime has been found in Southwest China, the nonlinear appearance of relatively matured form of stone chime at Sanxingdui site suggests the diffusion of the ritual musical system of Central Plain towards the surrounding regions during the late Shang period.