Alkali metasomatism occurs currently in Shituling uranium deposit，northern Guangdong province．Thewall rock alterations of orefield are strong，which mainly include muscovitization，potash feldspar alteration，chloritization， and sericitization． The alterations distribute planarly， and are consistent with the uraniummineralization．Based on the contrasting of the formation time of ore hosted rock，alkali rock，diabase anduraninite，and study on the geochemical features of the alkali rock，The study present that alkali metasomatismin the Shituling uranium deposit is formed by the metasomatism of the mantle fluid through deep extensionaltectonics．