Alkali- rich porphyry zones are widely distributed, but the geochemical behavior of elements in weathering process is rarely studied. Taking Yao’an alkali- rich porphyry in central Yunnan as an example, the study on its chemical weathering process is helpful to understand the controlling factors of element enrichment and dilution in the process of alkali rich porphyry soil- forming and enrich the theory of alkaline magmatic rock weathering soil- forming. Methods: The characteristics of mineral weathering, distribution characteristics of element content, trend of chemical weathering, migration and enrichment characteristics of elements and main controlling factors of alkali- rich porphyry weathering were analyzed. Results: The content of elements in the alkaline- rich porphyry regolith is inherited from the bedrock, which reflects the characteristics of in- situ weathering, and accords with the weathering characteristics of the rocks in the Upper Yangtze block of Yunnan under the North subtropical monsoon climate. Compared with continental upper crust composition (UCC), Ca, Na, K and other cations are strongly eluted and depleted, while Fe and Al are enriched. The chemical weathering process is mainly characterized by decarbonization of Ca, Na, K, Mg, Si and enrichment of Al and Fe. Ca and Na are mainly involved in the early stage of weathering. In the middle and late stages of weathering, the processes are mainly K and Mg removal and Al and Fe enrichment, accompanied by strong desilication. Conclusions: The order of activity of major elements was Ca>Na>K>Mg>Si>Al>Fe; On the one hand, the geochemical behavior of trace elements is mainly controlled by the behavior of major elements with similar geochemical properties. On the other hand, the trace elements are affected by Al, Fe oxides/hydroxides and adsorption of clay minerals. Sm, Nb, Sc, Th, Ti, U, Y, Cu, Cr and Ni are enriched in situ with weathering. The geochemical behavior of Ba, Rb, Sr is consistent with K, Na, Ca, Mg and other major elements, and leaching out with weathering.