There exist a lot of Cpx-peridotitic xenoliths in basanites of Maguan,Yunnan Province. Detailed researches on mineralogy and geochemistry have been done to understand the genesis of the xenoliths,The ressults show that there is no equilibrium between Cpx-peridotitic noddle and Its host rock,basanite,The formation depth of xenohths is relatively shallow(less than 60 km).The mantle area in which Cpx-peridotites are located has undergone light depletion and late stdge metasonmatism. All these xenoliths are occasional ones brought up tosurface by basanitic magma during its ascending.