There are four common metal words in Yi language: "gold", "silver", "copper" and "iron". These words can refer to metal elements, value and precious metals; It can also be used with some morphemes or words to refer to color. This paper adopts the method of synchronic and diachronic, compares the phonetic and semantic similarities and differences of four commonly used metal words in six major dialect areas of Yi language, and compares them with other relative languages of Tibeto Burman language group, trying to explore the etymology of these commonly used metal words in Yi language, and at the same time, compares these metal words with their corresponding color words, On the one hand, it reveals the historical evolution of some phonetics in Yi dialects, which provides some reference for the comparative study of kinship languages; On the other hand, it also shows the national culture and unique thinking mode of Yi people in metal understanding.