Abstract: The characteristics of soil microorganisms has been studied with three types of shifting sand dunes, semi-fixed dunes and stabilized dunes in southeastern Tengri Desert. In these dunes bacteria are predominant, actinomyces the next and fungi the least. The amount of microorganisms are greater in deeper horizon of the shifting dunes. The microorganism-crowded layer gradully moves upwards with the degrees of stabilization of the sand. The multiplication and the activity of various groups of microorganisms are related to the fertility of sand soil,plant growth and stabilization of the dunes.