The Kunyang phosphorite deposit in eastern Yunnan Province is a large-scale one characterized by marine sediments, tectonically located at the southwestern margin of the ancient Yangtze block. The Lower Cambrian Qiongzhusi Group outcropping widely in the ore district constitutes the roof rocks, which are also phosphor-bearing sedimentary formation. The Zhongyicun group containing phosphoric sedimentary formation and Xiaowaitoushan Group are the bottom of P-bearing sedimentary formation. All the features indicate that P-bearing sedimentary formation formed mainly in a littoral area containing supratidal, intertidal and subtidal shallow zones. Therefore, the deposit formed mainly in a sedimentary environment of either stable platform margin or a shallow continental shelf.