The red bed area in southwest of China often occurs many geological disasters, and causes serious casualties and property losses. The argillation intercalations were widely distributed in southwest red bed region, it was the worst of the engineering characteristics, structural planes in rock mass slope and was the key to red layer in southwest slope geological hazard control factors, along with all kinds of engineering geological problems. Based on many different period time sampling different intensity of hydration of clay layer, after the indoor experimental research and analysis, obtained the mineral composition, chemical elements and microstructure change rule of the evolution process from argillaceous rock to argillation intercalations in southweast area. According to test results of experiment, the evolution process is divided into three stages: ion exchange adsorption stage, minerals dissolved stage, mineral production phase stage.