Abstract: Through a careful observation to tafoni developed on glacial granite boulders in Eastern Pamir, the tafoni are classified into side-wall tafoni, basal tafoni, cellular tafoni and trough tafoni according to their morphological characteristics and positions. Their genesis is analyzed by combining with local terrain, air temperature and precipitation. The authors put forward that the tafoni are results from the joint effects of temperature difference weathering, salt weathering, mountain-valley wind deflation and a long time factor (since penultimate glaciation). The valley wind deflation plays a leading role in the genesis of side-wall tafoni.