Efflorescence , caused mainly by the soluble salts in the wall,is one of the most common and serious dis- eases threatening ancient murals. Research on the characteristics and activities of inorganic ions in murals will pro- vide a scientific reference basis for solving the problem of efflorescence in ancient murals. By simulating the mobility of soluble salts in murals , we tried to reveal the distribution and activities of inorganic ions. Detection and analysis of the concentration of soluble salts in fine mud layer , coarse mud layer and adobe layer at different height by ion chro- matography showed that Ca2+ , Na+ . and SOj' have the highest concentration in the fine mud layer of the test block . and therefore the highest mobility , followed by Cl- , N03- , Mg2+ ; and K+ which are weaker. The higher the mobility of the ion.the more it is enriched in the mural surface.and the higher the probability of its crystallization with other ions.and therefore the greater chance of damaging the mural. This study provides the basis for further re- search and the solution of salt damage of ancient murals.