The central Yunnan region is an important phosphate rock base on the western margin of the Yangtze continental block. The phosphate rock occurs in the carbonate rock phosphate-bearing rock series of the lower Cambrian Yuhucun Formation. The lithology is phosphate-bearing dolomite, phosphorite, and intercalated with siliceous rock. Siliceous rock occurs in a banded, massive or lenticular shape accompanied by phosphate-bearing dolomite or phosphate rock layer. Siliceous rock is an important research object for paleoenvironmental indication, stratigraphic correlation, and paleontological evolution records. This paper studies the petrological and geochemical characteristics of siliceous rocks associated with phosphorite in Chengjiang, Yiliang and Luliang areas of central Yunnan. The results show that the ratio of Al/(Al+Fe+Mn) in Chengjiang and Yiliang areas is less than 0.4, and that in Luliang area is greater than 0.4. The rare earth distribution curve shows a gentle left-leaning trend. Ce and Ti show negative anomaly characteristics. The total REE is relatively low and relatively enriched in HREE. The U/Th value is distributed between 1.0 and 8.8, all greater than 1. The Co/Ni ratio is between 0.04 and 0.27, showing the characteristics of relatively rich in Ni and poor in Co. Rock geochemistry indicates that the siliceous rocks in Chengjiang and Yiliang areas are mainly of hydrothermal origin, and the siliceous rocks in Luliang area are mainly of biological origin. Siliceous rocks are associated with phosphate rocks. Combined with regional geological data, it is believed that the huge reserves of phosphate rocks distributed along the Xiaojiang fault are derived from submarine exhalative genesis, forming super-large phosphate accumulation bases such as Chengjiang, Kunyang and Zhenxiong. While the Luliang area is far from the hydrothermal center. The formation of siliceous rocks is related to plankton. The genesis of its small-scale phosphate rocks is mainly of biological origin. It is also believed that submarine exhalative hydrothermal fluid provides temperature conditions for the life explosion. A large amount of phosphorus in the hydrothermal fluid provides abundant nutrients for life, laying a good foundation for the formation of phosphate rocks with huge reserves in this area and the life explosion in the Early Cambrian represented by the Chengjiang fauna.