Abstract: Ion microprobe offers in situ analyses of trace element abundances and isotopic compositions with a micrometer spatial resolution．It has a wide range of cosmochemical and geochemical applications． The technique has been particularly important in meteorite research where isotopic and chemical abundance anomalies are at their largest．This paper highlights the successful application of ion microprobe to a variety of research areas in cosmochemistry and geochemistry，and reports 26 major and trace element sensitivity factors determined in 11 silicate standards.